JPS601683B2 - Optimal recording characteristics automatic detection device for magnetic recording and playback equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for automatically detecting the optimum recording characteristics of a magnetic recording/reproducing machine, and more particularly to an apparatus for automatically detecting the optimum recording characteristics of a tape recorder having an absent recording machine.

There are different types of magnetic tape, such as L/H tape, chrome tape, and ferrichrome tape, and tape recorders are usually adjusted based on the standard tape for each type.
Even tapes of the same type have large differences in characteristics, and it is difficult to optimally set all recording characteristics for these various tapes.

In addition, some tape recorders have an absent recording machine, and when the above-mentioned optimal recording characteristic automatic detection device function is added to a device with such a function, the device is in the absent recording state. If the automatic detection operation is continued regardless of whether the setting is made or not, the recording of the absence will not be performed properly and the timing of the recording of the absence will be lost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an automatic optimum recording characteristic detection device for a tape recorder that can automatically detect the setting of the absent recording state and perform an appropriate absent recording operation, and can also automatically detect the optimum recording characteristic. It is to provide.

The device of the present invention is an automatic detection device for optimum recording characteristics of a tape recorder which has an absent recording function and automatically detects and adjusts the optimum recording characteristics in response to a start signal, and is capable of automatically detecting and adjusting the optimum recording characteristics in response to a start signal. A recording bias setting circuit, a recording level setting circuit, and a recording equalizer setting circuit in which a recording level and a recording equalizer can be set, respectively, and a storage means that can read and write information corresponding to each of a predetermined recording bias, recording level, and recording equalizer. In response to the power-on operation, the tape recorder detects that the tape recorder is set to an absent recording state and generates a first command signal, and detects that the tape recorder is not set and generates a second command signal. A recording state detecting means, a setting signal generating means for outputting each piece of information stored in the storage means as a setting signal in response to a first command signal, and generating a start signal in response to a second command signal. It is characterized by being configured to wait for.

The above-mentioned absentee recording detection means, setting signal generation means, storage means, etc. can be controlled by a desired program using a microprocessor such as a microcomputer, and are therefore small and highly reliable. A device will be obtained, and it will also be possible to automatically determine the settings for recording when the user is away.

The present invention will be explained below with reference to the accompanying drawings.

FIG. 1 is a schematic block diagram of an embodiment of the present invention, in which the recording level adjustment signal L (400Hz) and the recording equalizer (EQ) adjustment signal termination (1 plate Hz) are selected by a changeover switch. Uniformly selected line switch 2a
is input to.

The line switch 2a selects either the line input signal or the above-mentioned adjustment signal NAL (or FINH) and applies it to the flat amplifier 3. The increased signal is input to the recording level setting circuit 4, the level of which is varied and set to an appropriate level, and then applied to the recording equalizer setting circuit 5. The recording equalizer setting circuit 5 is configured to vary the equalizer characteristics, and its output is recorded on the tape 7 by the recording head 6 while being superimposed on the recording bias signal number B (100K ratio). The recording bias signal 〆B is applied to a recording bias setting circuit 8 for varying and appropriately setting the bias level, and its output is superimposed on the previous recording signal via a bias amplifier 9.

The tape recording signal is reproduced into an electrical signal by the reproduction head 101 and then sent to the reproduction equalizer circuit 11 and the flat amplifier 1.
2, the line amplifier 14 is connected to the line amplifier 14 via the switch 13.
is input.

The output of the line amplifier 14 becomes a line output via the line switch 2b. The output of the regenerative flat amplifier 12 is also converted to a DC level by a detection circuit 15 and becomes one input of a comparator 16.

The reference signal that is the other input to the comparator 16 is the D/A
The output of the converter 17 is used, and the converter 17 converts the parallel binary digital signal output from the port output PA of the PM 18 into a DC level. The output of the comparator 16 is applied to the boat input P, of the PIA 18. A binary digital signal is output from the boat output PB of the PM 18 and decoded by the decoder 19, followed by a control signal 101 for controlling the recording level setting circuit 4, the EQ setting circuit 5, and the recording bias setting circuit 8.
102 and 103.

In addition, the changeover switch 1 and line switches 2a, 2b' are controlled on/off by the port outputs P2 and P3 of the PIA18, respectively, and the boat output P4 of the PIA18 is connected to the mechanical system (mechanical system) and amplifier system (electrical system) of the tape recorder. ) is a control signal that controls the boat input P5.
Similarly, a predetermined control signal is applied from the mechanical system or the amplifier system, including a signal indicating whether or not an absent recording state is set.

Then, CPU20 as a central processing unit and CPU2
ROM (read only memory) 21a in which a program to control 0 is stored in advance and a RAM that can be freely written and read.
A (random access memory) 21 is provided, and a keyboard 22 for giving external commands is connected to the input port Pc of the PM 18.

In addition, during normal operation, power is supplied to the RAM 21 from the device power supply, but when the power is cut off, power is applied from a backup power source such as a battery, so that the stored contents are always retained. It has become possible to do so.

FIG. 2A shows a specific example of the recording level setting circuit 4, in which the 6-bit parallel digital control signal 101 of the decoder 19 controls the isopeder between the input/output line and the ground. The switching transistor Q,
It is composed of a resistance network (R, wave, . . . 3 waves) and D-FF'. The input/output ratio of the recording level corresponding to the control signal 101 is shown in FIG. The magnitude of the 6-bit control signal 101 is digitally represented in 64 steps from the minimum value 00H to the maximum value 3F (16-ship system display), and on the 00th, the control signal 101 is (000000) and the step 0 is 3F is (111111), indicating step 64, and the 20th is (1000) of the intermediate step.
00).

In this method, the recording level is changed stepwise in 64 steps using a 6-bit control signal, but if the number of bits is increased, the variable range will be expanded and the number of decompositions will increase. In addition, H'ma indicates that it is indicated by the 16 ship method,
The same applies to the other control signals 102 and 103. FIG. 3A shows another example of the recording level setting circuit 4, in which the impedance between the inverting input of the operational amplifier OP and the ground is varied by the control signal 101 to obtain the characteristics shown in FIG. 3B.

The circuits shown in FIGS. 2 and 3 above can be constructed at extremely low cost, and when controlling multiple channels, the characteristics can be precisely matched. For example, the recording level can be set to L,
Since both R channels can be controlled simultaneously with one control signal, the circuit configuration is further simplified. Figure 4A
, B are diagrams showing still another example of the recording level setting circuit 4, in which the digital control signal 101 is converted into a DC voltage by an A/D converter, and this voltage is applied to the drive circuit 4 in A.
01 is used to control a so-called voltage-controlled variable resistance element VCR 402 made of a C ship photocoupler to vary the recording level.

B controls the VCR 402 (L, R channels) directly with DC voltage. Figure C is a diagram showing the characteristics. In the circuits shown in A and 8, the transmission line for control only requires the use of one line for direct current voltage. It has the advantage of requiring less. FIG. 5A shows a specific circuit example of the recording bias setting circuit 8, in which the resistance value between the bias signal line and the ground is varied according to the 6-bit control signal 103 of the decoder 9. (R, 2R, ...32R),
It consists of D-FF and Inverter V.

Reference numeral 801 indicates a bias amplifier that increases 10 levels.

Box B shows how the bias signal current changes with respect to the control signal 103. 6A and 6B are circuit diagrams showing other examples of the recording bias setting circuit 8. A is a circuit diagram showing another example of the recording bias setting circuit 8. ) etc. to convert it into a DC voltage, the power supply voltage Vc of the bias oscillator 802
c is variable.

Note that EH indicates an erase head. B is for controlling the impedance of the photocoupler 803, which varies the output level of the bias oscillator 802, by the digital control signal 103. FIG. 8A shows a specific example of the recording equalizer setting circuit 5, in which the value of the capacitive element Cs for equalizer characteristics is changed according to the control signal 102 of the decoder 19.
It appropriately selects the amount of compensation for the Saramachi z signal, and consists of an operational amplifier OP, a switching transistor Q, a capacitor network (C, 2C, . . . 32C), a D-FF, etc.

8 shows the change in capacitance value with respect to the digital control signal 102, and C shows the frequency characteristic of the recording signal current using the digital control signal 102, that is, the capacitance value as a parameter. FIG. 9A is a diagram showing another example of the recording equalizer setting circuit 5, in which the gain of the amplifier 501 is controlled by the control signal 102.
, D-FF, switching transistor Q and resistor network (
R, 2R,...32R) to obtain the equivalent capacitance C.
This is to control x=(1-A)C.

In this case, A indicates the gain of the amplifier 501, C indicates the feedback capacitance of the amplifier 501, the input impedance is infinite, and the output impedance is zero. In this circuit, a resistor is used instead of a precision capacitive element as in the circuit of FIG. 8, so parts are relatively easy to obtain. B in the same figure shows the change characteristic of the equivalent capacitance Cx, and C shows the change characteristic of the recording current compensation amount.
FIG. 10 is an example of a schematic plan view of the keyboard 22, in which pressing the "AUTO" switch turns the device into
Automatically controlled by the PU 20, optimal adjustment operations for recording bias, recording level, and EQ characteristics are started.

Further, when the "MEMORY" key is pressed and one of the numeric keys is pressed, the optimum data of the recording bias, recording level and EQ characteristics automatically set for the tape to be used is stored in the RAM 21. Therefore, by pressing the "TAPE" key again and pressing the same number keys as above, the data can be read out. If the "TAPE" key is pressed but no numeric key is pressed, the automatically set state can be changed to the standard state of recording bias, recording level, and EQ characteristics. In this case, the standard state refers to a state in which the bias current control signal, recording level control signal, and EQ control signal are controlled by a signal corresponding to an intermediate step in the variable range (for example, 20H) and are adjusted using a standard tape. , which corresponds to the fixed bias and level/EQ condition of a tape recorder without automatic adjustment.

Immediately after the power is turned on, it is always set to this standard state unless it is in the recording mode.

This makes it possible to immediately record in standard conditions, just like a normal tape recorder, immediately after turning on the power without performing automatic settings. Also, in the standard state, the TONE signal is output from the output port P4 of the PIA18, and only at this time manual bias adjustment, level adjustment, EQ adjustment,
enable. This makes it possible to adjust the standard settings to suit the user's preferences. TON is required for automatic adjustment.
If the E signal is not output, this will be canceled no matter where the manual adjustment position is. FIG. 7 shows a manual bias adjustment circuit. In the figure, when the TONE signal becomes “H”, Q is turned on, Q2 is turned on, Q3 is turned on, and Q4 is turned on.
It turns off, VR becomes variable, and the output of the bias oscillator changes. When the TONE signal is L, Q is off, Q2 is off, Q3 is off, and Q is on, so that VR has a constant resistance value at the midpoint and the bias oscillation output also remains constant. Display lamp. "BIAS", "LEVEL", and "EQ" lamps are provided, and their blinking is controlled according to the operation of the device.

There is also a "TAPE" display, which uses a 7-segment display element to display the type of tape, that is, in the standard state, one of standard tape, chrome tape, and ferrichrome tape, according to the user's selection. , “1” is displayed for standard tape, and “1” is displayed for chrome and ferrichrome tapes.
2" and 3" are displayed.Also, when automatically adjusted setting data (corresponding to each digital control signal) is stored in or retrieved from RAM, the R
Tape numbers 1 to 9 corresponding to AM are displayed. below,
The operation of the above-mentioned apparatus will be explained according to the flowcharts shown in FIGS. 14A to 14K, with reference to the operation waveform diagrams of FIGS. 11 to 13 as necessary.

First, the chart in FIG. 14A shows an example in which the tape recorder has an absent recording function, which automatically determines whether the device is set to the absent recording state.

In other words, as soon as the power is turned on, the setting for recording while away is being made, or the control signal of Anka is PM1.
8 input port P5, the CPU 20'
Well, if the signal is judged and the absence recording is set,
Each command signal is outputted to set the device to the recording characteristics that were set immediately before the power was turned on. In other words, when setting up recording while the user is away, the user uses key operations to read out the recording level, recording bias, and EQ characteristics from the memory circuit 21 in advance so that they have values corresponding to the tape to be used, and then sets the tape recorder. Therefore, each characteristic value should be stored in the memory 21 when the power is turned off. Therefore, when the CPU 20 determines that the recording is set to the absence recording mode, the recording level, recording bias, and EQ characteristics are set by the respective setting circuits 4, 5, and 8 to the above characteristic values, and the recording operation is performed during the absence recording operation. is in a standby state. If the tape recorder is not set for recording during an absence, control signals 101, 102, and 103 are output so as to set each to the standard recording characteristics of a standard tape, for example.

After that, the system waits for a key input instruction.
Figure 14B shows "AUT" to start automatic recording characteristic adjustment.
This is a chart for setting the equipment when the "O" switch is pressed, and it determines whether it is in the "STOP" state or not in the "PAUSE" state and sets the rear device to the "REC/PLAY" state. do. At the same time, the operation of the recording bias manual adjustment circuit is prohibited,
Switch the line input switches S2 and S2b as desired. In addition, the tape counter is reset so that it is prohibited from stopping the tape in the 0" state.The operator then determines the type of tape set in advance and sets the recording level, bias, and EQ corresponding to the tape. Each setting circuit is controlled according to the characteristics.The following explanation assumes that a standard tape is used.At this time, the "BIAS", "LEVEL", and "EQ" lamps on the keyboard are all turned off. FIG. 14C is a chart for automatic magnetic tape detection, and shows the output port PA of PIA18.
The minimum value of the digital signal 00 days is output to D/
After being converted into an analog signal corresponding to day 00 by the A converter 17, it becomes the reference input of the comparator 16.

Then, the switch 1 selects L=40 plates z as the recording signal based on the output P2 of the PIA 18. In this case, the playback output is zero in the league tape portion, so the detector 15
The output of is zero volts, so the output of comparator 16 is a low level.

Then, at the same time as reaching the magnetic tape section, the reproduction level becomes high and the comparator output is inverted to a high level. This high level signal (P,) causes tape detection and resets the built-in tape counter to "n". mosquito)
This state is shown in period C in FIG. Figure 14D
is a chart for roughly adjusting the recording level to set the optimum recording level.

This adjustment is performed with the bias and recording equalizer set to standard settings. In other words, if you do not make this adjustment,
With respect to the bias current vs. playback level characteristic of the standard tape shown in Figure 12A, for tapes with different sensitivities such as 121, 122, and 123, digital conversion is necessary to bring the playback level into the range that can be converted into digital. Although it is necessary to widen the range, on the other hand, in order to accurately find the maximum value of the reproduction level of the bias current characteristic, the resolution of the digital conversion section must be about 0.1 dB. Therefore,
By making this level adjustment, the level is adjusted to point A in FIG. 12B, so that the resolution can be set to 0.1 and the range that can be digitally converted can be narrowed. Also, the reason why the level for crude steel was not set at the center value of 20 days was to widen the range of the higher level since the bias curve necessarily passes through point A in FIG. 12B.

A digital output indicating the standard level OA (001010) is generated at the output port PA, and the analog level corresponding to the OA value becomes the reference input of the comparator 16. At this time, the "TBIAS" lamp changes from an off state to a blinking state. And control input signal 1 of recording level setting circuit 4
A recording level value at which 01 changes appropriately and becomes equal to the reference input of the comparator 16 is selected. In this example, the first
As shown in period D in Figure 1, a bias research method is used. In other words, by comparing the playback level and the reference level, the difference is 1'2, 1/4, 1/8...
. . 1'64, and the recording level at which the playback level becomes equal to the reference level is detected by adding and subtracting the bell. Note that, of course, other methods may be used instead of the binary search method. At this time, if the reproduction level becomes high and reaches a level corresponding to the upper limit value 3F that can be used for subsequent digital processing, an error signal is output, and all the lamp displays are blinked to issue a warning that adjustment is not possible. When the recording level corresponding to the standard playback level OA is set, Fig. 14E
, F, recording bias settings are made according to the flowchart.

That is, the 6-bit digital control signal 103 is set to 00.
The playback level is varied in 64 steps from H to 3F, and each corresponding playback level is converted into a 6-bit digital signal and stored in memory, and when all playback is completed,
This is carried out by a so-called level sweep method that detects and sets the optimum recording bias using the contents of each memory. The playback level is digitized by the comparator 16 and the D/A converter 1.
According to 7, this is done by so-called successive approximation type A/D conversion, and the playback level is also converted to a value from 00H to 3F according to the 16 ship method, and playback levels outside the range cannot be processed, so the playback level is the 3F value. If it is included, an error signal will be generated and adjustment will not be possible. For example, the curve 61 in FIG. 12B,
This is the case as shown in 62. These playback characteristics will not appear because the recording level has been set in advance in flowchart D, but if the tape used is not in the optimal position due to user error (for example, if the tape should be used in the chrome position) When the tape is set to the L/H tape position, curves 61 and 62 are obtained. When reading the playback level at each bias current, there is a time lag from the recording head to the playback head, t = (distance between the recording head and the playback head)/tape speed, so the bias is set to B at t = 0 as shown in Figure 12C. , and after a time lag t, the playback level is A/D converted and written to RAM, and then the bias is set to B2 and the same procedure is repeated. For example, t, = 1.
64×100×10-3=6.4 as 00mSeC
More than a second is definitely necessary. Therefore, the time required to set the reproduction level can be reduced by increasing the bias at regular intervals and reading the data after each time t, as shown in FIG. In D of the same figure, the time for increasing the bias is set to ;L/2, and after setting the bias B, the bias is set to &, and after to seconds, the bias is set to B3, and the playback level is set to A/2 at the same time. D conversion is performed and this is written in the RAM as the reproduction level for bias B.

Continuing this in the same way, to x 64 t, = 3. The time is shortened by completing the writing of data using streak sand. Although to=t,/2 was used in this case, it is clear that the time can be shortened by making it shorter. Furthermore, if the occurrence of playback output (or cue signal) at bias B, is detected and the playback level adjustment is started, t becomes unlimited and can also be used in tape decks (two-head machines) that record and play at different times. It becomes possible.

Memo: The 64 pieces of playback data stored in the memory are stored in the CPU 201.
Judgment and arithmetic processing are performed from this.

That is, by determining the number of signals with the maximum reproduction level M,
For example, if it is 3 (generally n) or more, the corresponding minimum value B of the recording bias (actually, a digital signal indicating the corresponding control signal 103) is first stored.
However, if the reproduction level characteristics shown in Fig. 12E and F' are obtained, the maximum value of each is set to (M-1).
, (M-2), it is possible to prevent the cases shown in E and F from becoming unadjustable, and to prevent malfunctions due to dropouts or extreme fluctuations in the bell. Even if the maximum value M is decreased sequentially to (M-1) and (M-2) in this way, if the number of signals is not 3(n) or more, it is determined that adjustment is impossible and an error signal is generated. This operation is repeated again to determine the recording bias B2 in the same manner, and the average value B=(B, 1 B2)/2 of both is calculated using the previously determined value B.

After that, the optimum bias value B': B+N is determined. child)
N is an appropriate predetermined value, and by adding N, correction is made so that the average value calculation does not result in a shallow bias value. The playback levels during the sweep of the recording bias adjustment are shown in periods E and F' in FIG.

The digital signal serving as the control signal 103 corresponding to the optimum recording bias B' thus obtained is stored in a predetermined location in the memory, and the recording bias setting circuit 8 is controlled and set thereby. At this time "BIAS"
The lamp changes from flashing to constantly lit. FIG. 14 G, day is a flowchart for adjusting the recording level, in which the reference input of the comparator 16 is set to the reference level corresponding to the 20th, and the recording level is adjusted by the binary search method shown by period G in FIG. 13 A. A rough adjustment is made.

At this time, the "LEVEL" lamp changes from off to blinking.
Also in this case, if the reproduction level is outside the digital processing range, an error signal will be generated. When the rough level adjustment is completed, the signal adjustment is performed. In this case, as shown in FIG. Count the high number of times n.

If the counting result satisfies, for example, 8<n<12, the recording level at that time is set as the optimum recording level. If nku8
, n>12, the recording level is raised or lowered by one step, and compared and counted again. This operation is repeated, for example, four times until 8<n<12, and the tuning is performed. Further, the digital signal indicating the control signal 101 for setting the recording level obtained in this way is 3F or 00.
If it is a day, this is also treated as an error signal and adjustment is disabled.

Then, when the level is set and memorized again, "LEVEL"
The lamp is always on. The above operating waveforms are shown in FIG. 3A. Figure 14 1, J is a flowchart for adjusting the EQ (recording equalizer) characteristics. First, the recording signal is switched from Na L = 40 Hz to H = 1 Hz. At this time, the EQ lamp changes from off to blinking. After that, the EQ setting circuit 5 is controlled by the control signal 102, and the first
As shown in FIG. 3A, the recording level adjustment is performed in the same manner as the previous recording level adjustment. To describe only the different parts, in the fine adjustment stage, if the digital signal for the control signal 102 indicating the EQ characteristic is 00 days, an error signal will be generated, and if the 3F
If so, the bias is too deep, so reduce the recording bias by one step and adjust the recording level again.
It operates to perform EQ adjustment, that is, recording compensation amount adjustment.

In this case, if the above-described determination loop has been performed four times, it is determined that adjustment is not possible and an error signal is generated. Once the optimum EQ characteristics are created, set, and stored in this way, the "EQ" lamp lights up constantly and the adjustment is completed. Figure 14 K shows the device “STO”
3 is a flowchart for returning to the "P" state.

In the figure, the tape stops at the "0" position of the counter, but this is because the counter was reset at "n" at the start (n is a positive integer), so the tape is overlaid by a distance corresponding to the n count. ” will be run. This is to erase the signals (L, H) recorded during automatic adjustment.According to the present invention, the memory, CPU, P mountain, etc. can be configured with a microprocessor such as a microcomputer. Not only can an extremely small and highly reliable device be obtained, but also other operations such as control operations such as counters and timers can be performed simply by increasing the number of programs.

Another advantage is that the optimal recording characteristics are automatically determined for any type of tape.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of an embodiment of the present invention, FIG. 2A is a diagram showing an example of a recording level setting circuit, and B is a characteristic diagram thereof.
3A is a diagram showing another example of the recording level setting circuit, B is a characteristic diagram thereof, FIGS. 4A and B are diagrams illustrating still another example of the recording level setting circuit, C is a characteristic diagram thereof, 5A is a diagram showing one example of a recording bias setting circuit, 8 is a characteristic diagram thereof, FIGS. 6A and B are diagrams showing another example of a recording bias setting circuit, and FIG.
The figure shows an example of a manual control circuit for recording bias.
FIG. 8A is a diagram showing an example of a recording EQ setting circuit, B and C are its characteristic diagrams, FIG. 9A is a diagram showing another example of the recording EQ setting circuit, B and C are its characteristic diagrams, and FIG. 1 is a schematic diagram of the keyboard, FIGS. 11 to 13 are operational waveform diagrams, and FIG. 14 is a flowchart. Explanation of symbols of main parts 4... Recording level setting circuit,
5... Recording EQ setting circuit, 8... Recording bias setting circuit, 16... Comparator, 17... D/A converter, 20... CPU, 21... RAM, 21a... R
OM. Figure 3 Box boat Figure 2 Figure 4 Group of pictures Figure 7 Figure 7 Figures of many figures Traditional figure 4

Claims (1)

[Claims] 1. An automatic optimal recording characteristic detection device for a magnetic recording/playback machine that has an absentee recording function and automatically detects at least one optimal state of recording bias, recording level, and recording equalizer in response to a start signal, A recording bias setting circuit, a recording level setting circuit, and a recording equalizer setting circuit in which a recording bias, a recording level, and a recording equalizer can be respectively set according to each signal, and each information corresponding to each of the predetermined recording bias, recording level, and recording equalizer. and a storage means capable of reading and writing data, and detecting that the magnetic recording/reproducing device is set to an absent recording state in response to a power-on operation, and generating a first command signal to set the absent recording state. an absent recording state detection means for detecting that there is no recording and generating a second command signal; and a setting signal generation means for reading each piece of stored information in the storage means and outputting it as each of the setting signals in response to the first command signal. An apparatus for automatically detecting optimum recording characteristics of a magnetic recording/reproducing machine, characterized in that it waits for generation of the start signal in response to the second command signal.