JPS6218977B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a reel control device for a magnetic recording/reproducing device that requires high-speed tape drive, such as a data memory device for a computer or a large-sized video tape recorder. Traditionally, this type of reel control device has been
For example, an air system has been proposed in which tension feedback is applied by an air chamber to perform reel servo, and an air capstan is used to feed the tape, but this system requires sufficient high-speed and stable operation. However, in order to obtain the desired performance, an extremely complicated configuration would be necessary and the device would be expensive. Therefore, there is a desire for a reel control device that does not rely on the above-mentioned air system. Therefore, the present invention provides a novel reel control that can operate at sufficiently high speed and stability without using the above-mentioned complicated and expensive air system. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing one embodiment. FIG. 1 is a block diagram showing an embodiment of a video tape recorder to which the present invention is applied. In the embodiment shown in FIG.
A first tape reel 4 mounted on a first reel stand 3 rotated by a first motor 2, and a second tape reel 4 mounted on a second reel stand 6 rotated by a second motor 5. The direction from the first tape reel 4 to the second tape reel 7 (hereinafter referred to as the forward direction) is wound and mounted on a tape reel 7.
or in the opposite direction (hereinafter simply referred to as "reverse direction"). In addition, the above magnetic tape 1
While traveling, the tape passes through a rotating magnetic head device 8, and its tension is detected by a tension detector 9. In addition, the ratio of the maximum winding diameter and the minimum winding diameter of the magnetic tape 1 between each of the above-mentioned tape reels 4 and 7 is set to 4 times or less,
This embodiment is configured to operate when the ratio of the above-mentioned winding diameters is 4 times or less. Here, each of the above-mentioned motors 2 and 5 is a louving coil type DC motor such as a print motor, and the first motor 2 is driven by a first motor drive circuit 10 in which a driving electric power corresponding to a first angular velocity command voltage is connected to a first motor drive circuit 10. Further, the second motor 5 is supplied with drive power corresponding to the second angular velocity command voltage from the second motor drive circuit 11 . The first pulse generator 12 for generating a pulse signal with a number of pulses corresponding to the rotational speed of the first reel stand 3 includes a gear-shaped light-shielding disc 13 having 60 teeth; two pairs of light-emitting/light-receiving elements 14, each of which has a light-emitting part and a light-receiving part facing each other with a light-shielding disk 13 in between;
15, and the light shielding disc 13 is rotated integrally with the first reel stand 3. In addition, the above 2
The pair of light-emitting/light-receiving elements 14 and 15 are arranged at an offset angle of 90° with respect to the tooth pitch of the light-shielding disc 13. FIG. 2 shows an example of the first pulse generator 12 constructed using a photocoupler consisting of a light emitting diode and a phototransistor as each of the light emitting/light receiving elements 14 and 15 described above. In FIG. 2, 100 is a first phototransistor that performs photoelectric conversion such that when the base is irradiated with light, conduction occurs between the collector and the emitter.
Similarly, 101 is a second phototransistor. 102 is the above-mentioned first phototransistor 1
This is a first light emitting diode that irradiates light to the base of 00. Reference numeral 103 denotes a light emitting diode that irradiates the base of the second phototransistor 101 with light. The first light emitting diode 102 and the first photo transistor 100 and the second light emitting diode 103 and the second photo transistor 101 form two photo couplers 1.
04,105. Therefore, when the above-mentioned light shielding disk 13 is rotated integrally with the first reel stand 3, each phototransistor 100, 101 has its base intermittently irradiated with light from each light emitting diode 102, 103. Therefore, the first and second pulse signals having the number of pulses proportional to the rotation speed of the first reel stand 3 can be obtained from each emitter. The first pulse signal obtained at the emitter of the first phototransistor 100 is transmitted to the impedance converting transistor 100.
6 and a buffer amplifier 107, the signal is output from the first output terminal 108. Similarly, the second pulse signal obtained at the emitter of the second phototransistor 101 is transmitted to the transistor 109.
and is outputted from the second output terminal 111 via the buffer amplifier 110. Here, since the number of teeth of the light-shielding disc 13 is 60, each of the above-mentioned pulse signals has a pulse number of 60 pulses per rotation of the first reel stand 3. Furthermore, since the square photo couplers 104 and 105 (that is, the light emitting/light receiving elements 14 and 15) are arranged at an offset angle of 90 degrees with respect to the tooth pitch of the light shielding disk 13, the first With respect to the pulse signal, the phase of the second pulse signal advances by the offset angle corresponding to the rotation direction of the first reel stand 3, and
Or be late. Returning to FIG. 1, each pulse signal obtained from the first pulse generator 12 as described above is supplied to the rotational direction determination circuit 18 and rotational angular velocity detection circuit 17 of the first local feedback circuit 16. be done. The rotational direction discrimination circuit 18 discriminates the rotational direction (that is, the running direction of the magnetic tape 1) from the above-mentioned pulse signals, and outputs a discrimination output signal having positive or negative polarity depending on the rotational direction to an inverting circuit. Supply to 19. Moreover, the above-mentioned rotational speed detection circuit 17 corresponds to one rotation of the first reel stand 3.
A pulse signal 4 times the number of pulses of 240 pulses is synthesized from each of the above pulse signals, and this 4 times pulse signal is supplied to the counting circuit 20, and the above 4 times the number of pulses is integrated. A detection output signal of a voltage corresponding to the rotational speed of the reel stand 3 is supplied to the above-mentioned inverting circuit 19. Furthermore, the above-mentioned inverting circuit 19 operates to invert the polarity of the above-mentioned detection output signal according to the polarity of the supplied discrimination output signal, and the above-mentioned inversion circuit 19 operates to invert the polarity of the above-mentioned detection output signal according to the polarity of the supplied discrimination output signal, A first local feedback signal having a polarity and a voltage value proportional to the rotational angular velocity is negatively fed back to the first motor drive circuit 10 described above. Here, an example of a specific circuit configuration of the above-mentioned rotational direction determination circuit 18 is shown in FIG. In FIG. 3, a first signal input terminal 120 is supplied with a first pulse signal obtained by the first pulse generator 12 described above, and this first pulse signal is applied to a first D-type flip-flop. 121 data input terminal, first input terminal of first NAND gate circuit 122, fourth D-type flip-flop 12
3 and the third input terminal of the fourth NAND gate circuit 124. Furthermore, the above first pulse signal is applied to the inverter 1
25, the clock input terminal of the second flip-flop 126, the second NAND gate circuit 12
7, a data input terminal of a third D-type flip-flop 128, and a first input terminal of a third NAND gate circuit 129. Further, a second pulse signal obtained by the first pulse generator 12 described above is supplied to the second signal input terminal 130, and this second pulse signal is applied to the first D-type flip-flop 121. A clock input terminal, a third input terminal of the first NAND gate circuit 122, a data input terminal of the second D-type flip-flop 126, and a second NAND gate circuit 1
27 first input terminals. Furthermore, the above pulse signal is passed through the inverter 131 to the clock input terminal of the third D-type flip-flop 127, the third input terminal of the third NAND gate circuit 129, the data input terminal of the fourth flip-flop 123, and the fourth is supplied to the first input terminal of the NAND gate circuit 124. The above-mentioned first to fourth D-type flip-flops 121, 126, 128, and 123 output each Q output signal obtained by being triggered by the above-mentioned first or second pulse signal, respectively. The first to fourth NAND gate circuits 1 of
22, 127, 129, and 124, respectively. Further, the first to fourth NAND gate circuits 122, 127, 129, 12
4 supplies the NAND gate output signals of the Q output signal, the first pulse signal, and the second pulse signal to each input terminal of the 4-input NAND gate circuit 132. In the rotation direction determination circuit 18 configured as described above, there is a gap between the first pulse signal and the second pulse signal supplied from the first pulse generator 12 in the rotation direction of the first reel stand 3. Since there is a corresponding phase lead or lag, by comparing the phase with the above first pulse signal, the above first pulse signal can be determined.
The magnetic tape 1 corresponds to the rotation direction of the reel stand 3.
has a positive polarity voltage when it is traveling in the forward direction,
In addition, when traveling in the reverse direction, a discrimination output signal having a negative polarity voltage is output from the NAND gate circuit 13 with four inputs.
Signal output terminal 1 as NAND gate output signal of 2
Obtained at 33. Further, an example of a specific circuit configuration of the rotation angle detection circuit 17 described above is shown in FIG. In FIG. 4, a first signal input terminal 140 has a first signal input from the first pulse generator 12 described above.
This first pulse signal is supplied directly and via a delay circuit 143 consisting of a resistor 141 and a capacitor 142 to a first exclusive OR circuit 144 . This first exclusive OR circuit 144 outputs a pulse signal with twice the number of pulses of the above-mentioned first pulse signal as an exclusive OR output signal of each supplied signal, and converts this pulse signal into It is supplied to the first input terminal of the NOR gate circuit 145. Further, a second pulse signal obtained by the first pulse generator 12 described above is supplied to the second signal input terminal 140', and this second pulse signal is transmitted directly and via a delay circuit 143'. It is supplied to the second exclusive OR circuit 144'. This second exclusive OR circuit 144' outputs a signal with twice the number of pulses as the above second pulse signal as an exclusive OR output signal, and this signal is sent to the second exclusive OR circuit 144' of the above NOR gate circuit 145. Supplied to the input terminal. Therefore, the NOR gate circuit 145 outputs 240 pulses for one rotation of the first reel stand 3 as a NOR gate output signal having twice the number of pulses as each of the first and second pulse signals whose phases are shifted from each other. outputs a quadruple pulse signal having a pulse number of . Further, the quadrupled pulse signal obtained from the NOR gate circuit 145 is output from the first signal output terminal 146 as a counting signal to the counting circuit 20, and is also supplied to the monostable multivibrator 147 as a trigger signal. Ru.
The above monostable multiviprator 147
supplies the Q output signal obtained by being triggered by the above quadrupled pulse signal to the base of one transistor 149 of the buffer amplifier 148 constituted by a symmetrical transistor amplifier circuit, and also outputs the output signal to the base of one transistor 149. 150 to the base of the other transistor 151 of the buffer amplifier 148. Then, the output signal of the buffer amplifier 158 described above is integrated by an integrating circuit 154 consisting of a resistor 152 and a capacitor 153. Here, if the output signal from the monostable multivibrator 147 is directly integrated by the integration circuit 154, the output signal from the second reel stand will be affected by the offset, saturation voltage, etc. Since it is difficult to obtain an integrated output with sufficient linearity corresponding to the rotational angular velocity of 6 from the above-mentioned integration circuit 154, in order to eliminate the adverse effects on the above-mentioned monostable multivibrator 147, the above-mentioned buffer amplifier 148 is used. The output signal from the monostable multivibrator 147 is supplied to the integrating circuit 154 through the monostable multivibrator 147. Then, the integrated output signal obtained from the above-mentioned integrating circuit 154 is passed through the buffer amplifier 155 to the second
is supplied to the signal output terminal 156 of. Further, the above-mentioned integrated output signal outputted from the above-mentioned buffer amplifier 155 is supplied to a third signal output terminal 158 via an inverting amplifier 157 with a gain of 1. In the rotational angular velocity detection circuit 17 configured as described above, a pulse signal four times the number of pulses of 240 pulses per rotation of the first reel stand 3 is obtained at the first output signal terminal 146, and the second and the third signal output terminals 156, 158.
A voltage detection output signal corresponding to the rotational speed of the reel stand 3 is obtained. In addition, the second and third
The voltages of the respective detection output signals obtained at the signal output terminals 156, 158 of the reel holder 3 have opposite polarities, and their values change linearly with respect to changes in the rotational angular velocity of the first reel stand 3. It's summery. Therefore, the inverting circuit 1 is supplied with the discrimination output signal obtained by the rotation direction discrimination circuit 18 and the detection output signal obtained by the rotation angular velocity detection circuit 17 as described above.
9 selectively outputs the detection output signal from the second signal output terminal 156 or the third signal output terminal 158 of the rotational angular velocity detection circuit 17 according to the polarity of the discrimination output signal. , it is possible to output a first local feedback signal having a polarity corresponding to the rotational direction of the first reel stand 3 and having a voltage proportional to the rotational angular velocity. Further, FIG. 5 shows an example of a specific circuit configuration of the first motor drive circuit 10 to which the first local feedback signal is negatively fed. In FIG. 5, a first rotational angular velocity command signal is supplied to a first signal input terminal 160, and this first rotational angular velocity command signal is supplied to a positive input terminal of an operational amplifier 161. The above operational amplifier 16
1 is amplified by a power amplifier 162 and supplied to the first motor 2 from an output terminal 163 as driving power. Here, the operational amplifier 16
1 and the output of power amplification supply 162 are the first
The driving power supplied to the first motor 2 is fed back to the negative input terminal of the operational amplifier 161 through the second feedback resistors 164 and 165. This corresponds to the first rotational angular velocity command signal described above. Further, the first local feedback signal is fed back to the negative input terminal of the operational amplifier 161 via a buffer amplifier 166 and a third feedback resistor 167. Through negative feedback control, the first motor 2 driven by the above drive power stabilizes the first reel stand 3 at a predetermined rotation speed determined by the above first rotational angular velocity command signal. can be rotated to Therefore, by rotating the first reel stand 3 with the first motor 2 driven by the first motor drive circuit 10 configured as described above, the first reel stand attached to the first reel stand 3 is rotated. Even if the winding diameter of the magnetic tape 1 on the tape reel 4 changes and the rotational inertia of the first reel stand 3 changes, the first
Negative feedback control using the local feedback signal corrects the above-mentioned change in inertia, so that stable rotation is always maintained. Next, in FIG. 1, the second reel stand 6 is
The above-described first pulse generator 12, first local feedback circuit 16, and first motor drive circuit 10,
A second pulse generator 21, a second local feedback circuit 22, and a second motor drive circuit 11 with similar configurations
As a result, the rotational speed is stably rotated at the rotational speed specified by the second rotational angular velocity command voltage. In this second reel stand 6 as well, changes in inertia due to changes in the winding diameter of the magnetic tape 1 are corrected by negative feedback control using a second local feedback signal from the second local feedback circuit 22. Here, in the second local feedback circuit 22,
From the first and second pulse signals obtained by each light emitting/light receiving element 24, 25 when the light shielding disk 23 of the second pulse generator 21 is rotated integrally with the second reel stand 6. The rotational direction discrimination circuit 26 obtains a polarity discrimination output signal corresponding to the rotational direction of the second reel stand 6, and supplies this discrimination output signal to the inversion circuit 27 and the arm inversion circuit 28. ing. Further, from the above first and second pulse signals, the rotational angular velocity detection circuit 29 obtains a pulse signal four times the number of pulses of 240 pulses for one rotation of the above reel stand 6, and the second reel A detection output signal having a voltage proportional to the rotational angular velocity of the table 6 is obtained, the above quadruple pulse signal is supplied to the control gate circuit 30, and the above detection output signal is further supplied to the inversion circuit 27, and the voltage variable type The clock pulse generator 31 of FIG. The clock pulse generator 31 sends a clock pulse signal having a frequency corresponding to the voltage of the detection output signal (that is, the rotational angular velocity of the second reel stand 6) to the control gate circuit 30 at the first and second gates.
It is supplied through the gate circuits 32 and 33 of. Note that the frequency of the above clock pulse signal is Hz ~
It is a low frequency signal of several tens of Hz. Further, the above-mentioned arm reversing circuit 28 is supplied with the above-mentioned discrimination output signal and is obtained by detecting with the tension detector 9 whether the tension of the magnetic tape 1 is above or below a specified value. When the detection output signal is supplied and the tension of the magnetic tape 1 is other than the specified value, the first or second gate circuit 3 is activated.
A gate control signal is selectively supplied to terminals 2 and 33 according to the above-mentioned discrimination output signal. Here, an example of a specific circuit configuration of the above-mentioned arm reversing circuit 28 is shown in FIG. In FIG. 6, the above-mentioned discrimination output signal is supplied to the first signal input terminal 170, and this discrimination output signal is supplied to the first and second AND gate circuits 17.
1,172. Further, the above discrimination output signal is transmitted to the third and fourth AND gate circuits 17 via an inverter 173.
4,175. Further, the second signal input terminal 176 receives a logic "0" from the tension detection circuit 9 when the tension of the magnetic tape 1 is below a specified value.
A detection output signal is supplied, and this detection output signal is supplied to the other input terminals of the first and fourth AND gate circuits 171 and 175. Further, the third signal input terminal 177 is supplied with a detection output signal from the above-mentioned tension detector 9, which indicates a logic "0" when the tension of the magnetic tape 1 exceeds a specified value. This detection output signal is supplied to the other input terminals of the second and third AND gate circuits 172 and 174. The AND output signals of the first and second AND gate circuits 171 and 174 are outputted from the first output signal terminal 179 via the first NOR gate circuit 178, and The AND gate output signals of the four AND gate circuits 172 and 175 are transmitted to the second NAND gate circuit 180.
The signal is outputted from the second signal output terminal 181 via. In the arm reversing circuit 28 configured as described above, when the tension of the magnetic tape 1 is at the specified value, the second and third signal input terminals 17 are
6 and 177 are set to logic "1", and output signals of logic "0" are obtained at the first and second signal output terminals 179 and 181, respectively, regardless of the running direction of the magnetic tape 1. Furthermore, when the magnetic tape 1 falls below (or above) the specified value while running in the forward direction, the first signal input terminal 170 receives a positive polarity voltage, that is, logic "1" because it is running in the forward direction. A discrimination signal is supplied to the second signal input terminal 1.
76 (or the third signal input terminal 177), the output signal of logic "0" is supplied to the signal output terminal 179 (or the second signal output terminal 18).
1), a logic "1" output signal is obtained. Further, when the magnetic tape 1 reaches a tension below (or above) a specified value while running in the reverse direction, an output signal of logic "1" is obtained at the second signal output terminal 181 (or at the first signal output terminal 179). Then, the output signal from the first signal output terminal 179 obtained in the arm reversing circuit 28 is supplied to the first gate circuit 32 as a gate control signal, and the output signal from the second signal output terminal 181 is supplied as a gate control signal. The signal is supplied as a gate control signal to the second gate circuit 33.The first and second gate circuits 32, 33 operate during the period when each of the gate control signals is at logic "1". The gate is opened to allow the clock pulse signal from the clock pulse generator 31 described above to pass through.Therefore, the clock signal obtained via the first gate circuit 32 is transmitted in the forward direction (or reverse direction) of the magnetic tape 1.
It is output only during the period when the tension is below (or above) the specified value while driving, and is sent to the control gate circuit 3 as a count-up correction signal.
0. Further, the clock pulse signal obtained through the second gate circuit 33 is generated only during the period when the tension is above (or below) the specified value while the magnetic tape 1 is running in the forward direction (or reverse direction). The signal is output and supplied to the control gate circuit 30 described above as a countdown correction signal. Furthermore, in FIG. 1, the 8-bit counting circuit 20 counts the quadruple pulse signals from the rotational angular velocity detection circuit 17 of the first local feedback circuit 16, and outputs a signal every 256 pulses. Output. The output signal of the counting circuit 20 is supplied to the pulse generating circuit 34, and a clear command signal and a latch command signal are obtained from the pulse generating circuit 34 every 256 pulses of the quadruple pulse signal. The above clear command signal is sent to the control gate circuit 3.
0 and is also supplied to the clear input terminal of the 10-bit up-down counter 35.
Further, the latch command signal described above is transmitted to the latch circuit 36.
is supplied to the latch input terminal. Also, the up-down counter 3 of the above bit
5 is supplied with a count-up pulse signal and a count-down pulse signal from the control gate circuit 30, and a 10-bit count output signal obtained by counting each pulse signal for each clear command signal is sent to the latch circuit. 36 in parallel.
Further, the latch circuit 36 latches the count output signal for each latch command signal,
It is supplied to a control input terminal of a digitally controlled variable divider 37. Here, an example of a specific circuit configuration of the above control gate circuit 30 is shown in FIG. In FIG. 7, a quadruple pulse signal from the rotational angular velocity detection circuit 26 of the second local feedback circuit 22 is supplied to the first signal input terminal 190,
This quadrupled pulse signal is sent to the first NAND gate circuit 1.
91 is supplied to one input terminal. Also, the second
A count-up correction signal obtained via the first gate circuit 32 described above is supplied to the signal input terminal 192' of the circuit, and this count-up correction signal is supplied to one input terminal of the second NAND gate circuit 192. Ru. Furthermore, a third signal input terminal 19
3 is supplied with a countdown correction signal obtained via the second gate circuit 33 described above, and this countdown correction signal is supplied to one input terminal of the third NAND gate circuit 194. Also,
A clock pulse signal from the clock pulse generator 31 described above is supplied to the fourth signal input terminal 195, and this clock pulse is used as a trigger signal to drive the monostable multivibrator 19.
6. Furthermore, the fifth signal input terminal 197 is supplied with a clear command signal obtained by the pulse generating circuit 34 described above, and this clear command signal is supplied to the inverter 199 via a 2-bit counting circuit 198. Ru. The sixth signal input terminal 200 is supplied with an operation mode signal that becomes logic "0" while the magnetic tape 1 is running, and this operation mode signal is applied to one input of the first NOR gate circuit 201. Supplied to the terminal. A Q output signal from a monostable multivibrator 196 triggered by the clock pulse signal is supplied to the other input terminal of the second and third NAND gate circuits 192 and 194, and The output signal of the second NAND gate circuit 192 is supplied to one input terminal of the fourth NAND gate circuit 202, and the output signal of the third NAND gate circuit 194 is supplied to the fifth NAND gate circuit 204 via the inverter 203. Supplied to one input terminal. Further, the output signal of the above 2-bit counting circuit 198 is supplied to one input terminal of the second NOR gate circuit 205 via the inverter 199, and the output signal of this second NOR gate circuit 205 is It is supplied to the other input terminal of the first NOR gate circuit 201, the fourth NAND gate circuit 202, and the fifth NAND gate circuit 204. Furthermore, the output signal obtained from the first NOR gate circuit 201 is supplied to the other input terminal of the first NAND gate circuit 191 and the second NOR gate circuit 205. In addition, the first and fourth NAND gate circuits 191 and 202 described above
Each of the output signals obtained is supplied to each input terminal of the third NOR gate circuit 206. The output signal obtained from the NAND gate circuit 206 is output as a count-up signal from the first signal output terminal 207, and the output signal obtained from the fifth NAND gate circuit 204 is output as a count-down signal as a second signal. It is output from the output terminal 208. In the control gate circuit 30 configured as described above, while the magnetic tape 1 is running, the first NOR gate circuit 201 is activated by the logic "0" operation mode signal supplied to the sixth signal input terminal 200. Since the output signal is logic "1", the first NAND gate circuit 191 is opened, and a pulse signal four times the number of pulses proportional to the rotational angular velocity of the second reel stand 6 is outputted as the first signal. available at terminal 207. When the tension of the magnetic tape 1 is at the specified value, the count-up correction signal and count-down signal are not supplied to the second and third signal input terminals 192' and 193. The pulse signal is directly supplied to the up-down counter 35 as a count-up signal. Further, when the tension becomes less than (or more than) a specified value while the magnetic tape 1 is running in the forward direction (or in the reverse direction), a count-up correction signal is sent from the first gate circuit 32 to the second signal input terminal 1.
92', an output signal obtained by superimposing this count-up correction signal on the above-mentioned quadruple pulse signal is obtained at the first signal terminal 207, and this signal is supplied to the above-mentioned up-down counter 35 as a count-up signal. do. Furthermore, the above magnetic tape 1
When the tension becomes more than (or less than) the specified value while the is running in the forward direction (or in the reverse direction), a countdown correction signal is supplied from the second gate circuit 33 to the third signal input terminal 193, and this countdown is started. Since the correction signal is obtained at the second signal output terminal 208, this countdown correction signal is supplied to the up-down counter 35 as a countdown signal. At this time, the quadrupled pulse signal obtained at the first signal output terminal 207 is supplied to the up-down counter 35 as a count-up signal. Therefore, the latch circuit 36 latches the count output signal obtained by counting the pulse numbers of the count-up signal and count-down signal from the control gate circuit 30 to the clear command signal by the up-down counter 35 for each latch command signal. Contents (10
If the magnetic tape 1 is running at a specified tension, the bit digital signal) will be 256 times the reciprocal of the winding diameter ratio of the second tape reel 7 to the first tape reel 4, and If the tension of the magnetic tape 1 is other than the specified value, the count result of the up-down counter 35 is a corrected value based on each of the above-mentioned correction signals. For example, when the magnetic tape 1 is running with a specified tension, the winding diameter ratio of the second tape reel 7 to the first tape reel 4, that is, the second
If the winding diameter of the first tape reel/the winding diameter of the first tape reel is 1, the above up-down counter 35
The counting result is 256 (i.e. 2 ⁸ ),
Ten digital signals whose ninth bit is logic "1" are latched into the latch circuit 36 described above.
Table 1 shows some of the logic values of the digital signals latched by the latch circuit 36. In Table 1, "1" and "0" indicate the logical value of the digital signal.

[Table] Furthermore, the digitally controlled variable divider 37 has a voltage division ratio that is varied according to the contents of the latch circuit 36 as described above, and is supplied via the slope limit setter 38 and receives an operation input. The voltage obtained by dividing the voltage by the above voltage division ratio is
The rotation angular velocity command voltage is supplied to the second motor drive circuit 11 described above. Further, the above-mentioned operation input voltage is passed through a fixed divider 39 with a voltage division ratio of 1/4 to the above-mentioned first rotational angular velocity command signal.
is supplied to the motor drive circuit 10 of. Here, an example of a specific circuit configuration of the digitally controlled variable divider 37 is shown in FIG. In FIG. 8, ten resistors 211, 21 are connected in series between the output terminal 210 and the ground.
2,213,214,215,216,217,
Among 218, 219, and 220, the resistor 211 on the ground side has a resistance value of 2.R, and each of the other resistors 212, 213, 214, 215, 216, 2
17, 218, 219, and 220 have a resistance value of R. In addition, each of the above-mentioned resistors 211, 212, 21
3,214,215,216,217,218,
219 and 220, and each other end is connected to the first to tenth switches 2.
21, 222, 223, 224, 225, 22
10 resistors 231, 232, 234, 235, 23 selectively connected to ground or input terminal 241 via 6, 227, 228, 229, 230
6, 237, 238, 239, and 240 each have a resistance value of 2·R. Each of the resistors 212, 213 whose resistance value is R,
214, 215, 216, 217, 218, 21
9,220 and a resistor 211,2 whose resistance value is 2・R
31,232,233,234,235,23
6,237,238,239,240, R
-2・R ladder circuit is configured. And the first to tenth control input terminals 25
1,252,253,254,255,256,
257, 258, 259, 260 are loaded with the output signal of the latch circuit 36 in parallel, and this signal causes each of the switches 221, 22 to be
2,223,224,225,226,227,
228, 229, 230 are each of the above resistors 23
1,232,233,234,235,236,
One end of each of 237, 238, 239, and 240 is grounded if the above signal is logic "0", and it is grounded if the signal is logic "1".
If so, a selection operation is performed to connect it to the input terminal 241. Therefore, the variable divider 37 configured as described above
are the first to tenth control input terminals 251, 25
2,253,254,255,256,257,
The voltage division ratio is digitally controlled according to the signals loaded in parallel to 258, 259, and 260, and the voltage obtained by dividing the operation input voltage supplied to the input terminal 241 using this voltage division ratio is used as the second rotational angular velocity command voltage. It is output from the output terminal 210 as For example, when the winding diameters of the first tape reel 4 and the second tape reel 7 are equal (that is, the winding diameter ratio is 1), each control input terminal 251, 252, 253, 254 is ,25
As is clear from Table 1 above, the 10-bit digital signals loaded in parallel to 5,256, 257, 258, 259, and
0, 0, 0, 0, 0, 0, 0, 1, 0], the signal is input via the ninth switch 259 by the signal of the ninth bit (logic "1"). The operating voltage is supplied to the resistor 239, and each of the other resistors 231, 232, 233, 234, 235, 23
6,237,238,240 are other switches 25
1,252,253,254,255,256,
257, 258, and 260, the voltage division ratio is 1/4. Table 2 shows some of the voltage division ratios obtained by the variable divider 37.

[Table] In Table 2, “0” and “1” indicate the
10 switches 251, 252, 253, 254,
255, 256, 257, 258, 259, 26
"0" indicates the operating state of each resistor 231, 2.
32,233,234,235,236,23
7,238,239,240 is grounded,
"1" indicates a state connected to the input terminal 241, and corresponds to the logic value of the 10-bit digital signal obtained by the latch circuit 36 described above. That is, the first reel stand 3 is rotated.
The driving power to the motor 2 is obtained by dividing the operation input voltage into 1/4 by the fixed divider 39.
The rotational angular velocity of the second reel base 6 is determined by the rotation angular velocity command voltage.
The driving power to the motor 5 is obtained by dividing the operation input voltage by voltage division corresponding to the winding diameter ratio of each tape reel 4, 7 using the digitally controlled variable divider 37 configured as described above. Since the second rotational angular velocity command voltage changes, the winding diameter ratio of the magnetic tape 1 mounted between the first tape reel 4 and the second tape reel 7 changes sequentially as it runs. Even when the voltage changes, the vehicle always travels at a speed determined by the operating input voltage without relaxing. Furthermore, since the latch circuit 36 supplies the variable divider 37 with a 10-bit digital signal that has been corrected for tension fluctuations during the running of the magnetic tape 1, the magnetic tape can be read while the tension is always at the specified value. 1 will be run. Further, in this embodiment, the operation input voltage supplied to the fixed divider 39 and the variable divider 37 can be arbitrarily varied from a positive potential to a negative potential by a speed adjustment variable resistor 40. As a result, the magnetic tape 1 is run in the forward or reverse direction at an arbitrary speed. In addition, when adjusting the running speed of the above magnetic tape 1,
If the gradient of change in the operating input voltage (hereinafter referred to as slope) is too large by rapidly changing the resistance value of the variable resistor 40, the motors 2 and 5 that rotate the reel stands 3 and 6 will be correctly interlocked. In order to prevent this from becoming impossible to drive, a tilt limit setting device 38 is provided. An example of a specific circuit configuration of the above-mentioned slope limit setter 38 is shown in FIG. In FIG. 9, a differential amplifier 270 has its positive input terminal grounded via a resistor 271, and its negative input terminal connected to an input terminal 273 via an input resistor 272. It constitutes an amplifier circuit 274, which supplies its power to a constant current circuit 275 and a first feedback resistor 27.
6 to its negative input terminal. Further, the constant current circuit 275 includes four bridge-connected diodes 277, 278, 279, 2
80, is configured to operate in both directions from a variable resistor 281 and a transistor 282,
Its output side is grounded via a capacitor 283 and connected to the negative input terminal of the differential amplifier 270 via a second feedback resistor 284, and the operating input voltage is used as the terminal voltage of the capacitor 283. This operating input voltage is output from an output terminal 286 via a buffer amplifier 285. Note that the input terminal 273 is supplied with an input voltage that can be arbitrarily varied up to a positive potential by the speed adjusting variable resistor 40 described above. Therefore, the slope limit setter 38 configured as described above
In this case, the time constant for charging and discharging the capacitor 283 is determined by the current flowing through the constant current circuit 275, so the input voltage supplied to the input terminal 273 is rapidly changed by adjusting the resistance of the speed adjusting variable resistor 40. Also, the slope of the operation input voltage obtained at the output terminal 286 is more limited by the above-mentioned time constant, so that it does not exceed a predetermined slope. Note that the current flowing through the constant current circuit 275 can be arbitrarily determined by adjusting the resistance value of the variable resistor 281, and the limit of the slope of the operation input voltage can be arbitrarily determined. Therefore, the fixed divider 39 is supplied with the operating input voltage obtained from the above-mentioned slope limit setting device 38.
and the first and second operating input voltages obtained via the variable divider 37 are varied with a slope such that changes in the rotation of each reel stand 3, 6 can be correctly moved relative to each other. Therefore, in the embodiment with the above-mentioned configuration,
A digital signal having a value corresponding to the winding diameter ratio of the magnetic tape 1 wound on the first and second tape reels 4 and 7 is obtained as a counting result in the up-down counter 35, and this digital signal is used to control the winding. Since the second motor 5 is driven by the drive power according to the second rotational angular velocity command signal obtained through the variable divider 37 which is controlled to a voltage division ratio corresponding to the diameter ratio, the second motor 5 described above The second reel stand 6 rotated at the rotation speed 5 is rotated at an optimum rotational angular velocity for running the magnetic tape 1 without slack at the above-mentioned winding diameter ratio. The tension of the running magnetic tape 1 is determined by correcting the count result of the up-down counter 35 using the count-up correction signal or count-down correction signal from which the detection output signal of the tension detector 9 is obtained, and By correcting the voltage division ratio of 37, it is always kept at the specified value. As a result, fluctuations in the tension of the magnetic tape 1 due to torque errors of the motors 2 and 5 are corrected. Furthermore, the change in the rotational inertia of each reel stand 3, 6 caused by the change in the winding diameter of each tape reel 4, 7 due to the running of the magnetic tape 1 is caused by each local feedback circuit 1 of each motor drive circuit 10, 11.
It is corrected by each negative feedback control by 6 and 22. Furthermore, the magnetic tape 1 described above can be run in the forward or reverse direction at an arbitrary speed by adjusting the operation input voltage using the variable resistor 40 for speed adjustment. Here, when changing the running speed of the magnetic tape 1, since the slope of the operation input voltage is limited by the slope limit setting device 38, each reel stand 3, 6 can change the rotational angular velocity of each other. Changes are made while maintaining interlocking relationships. Therefore, the magnetic tape 1 is always stably run with a constant tension even at any speed in the forward or reverse direction. In the above-described embodiment, the contents once latched in the latch circuit 36 are retained even if tape running is stopped. After installing on 6,
When running the magnetic tape 1 for the first time, a digital signal having a value corresponding to the winding diameter ratio of the magnetic tape 1 on each tape reel 4, 7 is sent to the latch circuit 3.
6 is not latched, the magnetic tape 1 is run by, for example, low-speed tape feeding by the capstan and reel constant torque winding mode.
During this time, the above winding diameter ratio may be latched in the latch circuit 36. In addition, if the magnetic tape 1 is not to be removed, for example, the latch circuit 3 may be connected using a CMOS-IC.
6 and drive the latch circuit 36 using a non-interruptible secondary battery power source, most of the above operations can be omitted. Furthermore, in the embodiment described above, the mutual winding diameter ratio is calculated directly by the up-down counter 35, but for example, the tape running speed at the time of calculating the winding diameter ratio is precisely defined, and the first Pulse signals corresponding to each rotation of the reel stand 3 and the second reel stand 6 are counted by two independent 10-bit counters, and each counting result is latched into two latch circuits to perform two digital controls. By controlling the voltage division ratio of the type variable divider, it is possible to correct the absolute winding diameter as well as the winding diameter ratio. Furthermore, in the embodiment described above, the angular velocity of the rotation of each reel stand 3, 6 is controlled by each rotation angular velocity command signal obtained from the operation input voltage. It is also possible to perform speed feedback according to the running speed and use the above-mentioned rotational angular velocity command signals as the running speed command signals. As is clear from the description of the above-mentioned embodiments, according to the present invention, each reel stand to which a pair of reels on which tape is wound and mounted, a pair of motors for rotating the reel stand, and each of the above-mentioned reel stands are provided. A pair of motor drive circuits that drive the motors, a pair of pulse generators that generate pulse signals with a number of pulses corresponding to the rotation of each of the reel stands, and a speed signal that specifies the running speed of the tape that is transmitted to each of the motors. A pair of speed specifying means supplied to the drive circuit and feedback control of each of the motor drive circuits based on pulse signals from each of the pulse generators to run the tape at a running speed specified by the speed signal. a local feedback circuit; a counting means for obtaining a counting output according to a tape winding diameter ratio of the pair of reels by counting one pulse signal from the pair of pulse generators according to the other pulse signal; Controlling the speed signal supplied to one motor drive circuit according to the tape winding diameter ratio of the pair of reels by the counting output of the counting means, and decreasing the speed in response to an increase in the winding diameter of the controlled reel; A control means for running the tape between the pair of reels without slack by increasing the speed in response to a decrease in the winding diameter, and a tension detection device for detecting whether the tension of the tape has increased or decreased from a specified value. correcting the count output of the counting means based on the detection output of the tension detection means, reducing the tension when the tension increases above the predetermined value, and decreasing the tension below the predetermined value. By having a correction means for increasing the tension and maintaining the tape tension at a predetermined value, the magnetic tape can be run at a constant tension and at any speed with a simple circuit configuration. This makes it possible to provide a highly practical reel control device. That is, in the reel control device according to the present invention,
A pair of pulse generators generate pulses corresponding to the rotation of each reel stand for each motor drive circuit of a pair of motors that rotate each reel stand on which a pair of reels on which tape is wound is attached. By performing feedback control based on a number of pulse signals, the tape can be run at an arbitrary running speed specified by the speed signal given by the speed specifying means. Further, by counting the pulse signals of one of the pair of pulse generators according to the other pulse signal, a counting output corresponding to the tape winding diameter ratio of the pair of reels is obtained, and this counting output is used to By controlling the speed signal supplied to one motor drive circuit according to the tape winding diameter ratio of the reels, the tape runs between the pair of reels without slack, and the tape runs between the pair of reels. The tape tension can be maintained constant by detecting the tape and correcting the counting output of the counting means based on the detected output. Therefore, in the reel control device according to the present invention, the control means for controlling the speed signal supplied to one of the motor drive circuits has speed control and tape tension for running the tape without slack between the pair of reels. With a simple circuit configuration commonly used for tension control to keep the magnetic tape constant, it is possible to run the magnetic tape at an arbitrary speed with a constant tape tension without relaxing it.

[Brief explanation of the drawing]

FIG. 1 is a block diagram schematically showing one embodiment of the present invention. FIG. 2 is a circuit diagram of a pulse generator applied to the above embodiment. FIG. 3 is a circuit diagram of a rotational direction determination circuit applied to the above embodiment. FIG. 4 is a circuit diagram of a rotational angular velocity detection circuit applied to the above embodiment. FIG. 5 is a circuit diagram of a motor drive circuit applied to the above embodiment. 6th
The figure is a circuit diagram of an arm inversion circuit applied to the above embodiment. FIG. 7 is a circuit diagram of a control gate circuit applied to the above embodiment. FIG. 8 is a circuit diagram of a variable divider applied to the above embodiment. FIG. 9 is a circuit diagram of a slope limit setter applied to the above embodiment. 1... Magnetic tape, 2, 5... Motor, 3, 6
... Reel stand, 4, 7 ... Tape reel, 9 ...
Tension detector, 10, 11... Motor drive circuit, 12, 21... Pulse generator, 16, 22...
... Local feedback circuit, 30 ... Control gate circuit, 35
...up-down counter, 36...latch circuit, 37, 39...divider.

Claims (1)

[Scope of Claims] 1. Each reel stand on which a pair of reels with tape wound thereon is mounted, a pair of motors for rotating each of the reel stands, and a pair of motor drive circuits for driving each of the motors. , a pair of pulse generators each generating a pulse signal with a number of pulses corresponding to the rotation of each of the reel stands, and speed specifying means for supplying a speed signal specifying a running speed of the tape to each of the motor drive circuits; Performing feedback control of each of the motor drive circuits based on pulse signals from each of the pulse generators,
A pair of local feedback circuits that run the tape at a running speed specified by the speed signal, and a pair of pulse generators that count the pulse signals of the other according to one pulse signal of the pair of pulse generators. a counting means for obtaining a counting output according to a tape winding diameter ratio of the pair of reels; and a counting means for controlling a speed signal supplied to one of the motor drive circuits according to the tape winding diameter ratio of the pair of reels by the counting output of the counting means. By decreasing the speed in response to an increase in the winding diameter of the control side reel, and increasing the speed in response to a decrease in the winding diameter,
control means for running the tape without slack between the pair of reels; tension detection means for detecting whether the tension of the tape has increased or decreased from a specified value; and counting by the counting means based on the detection output of the tension detection means. The tape tension is maintained at a predetermined value by correcting the output, decreasing the tension when the tension increases above the predetermined value, and increasing the tension when the tension decreases below the predetermined value. A reel control device comprising a correction means.