JPH0675078B2 - Oscilloscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an oscilloscope that simultaneously displays characters and observed waveforms on a tube surface.

(Prior Art and its Problems) Conventionally, a method of receiving a character signal from a character signal source such as a computer and visually displaying a character on a cathode ray tube or the like is well known. The term "character" used here is a general term for characters, numbers, symbols, figures, and the like. However, the conventional character display method of this type is classified into two types, that is, a raster scanning method or a vector display method. The former is a method in which a character to be displayed is divided into a large number of dots (dots), that is, coordinate signals, and a certain coordinate position is displayed on a cathode ray tube display device by, for example, bright spots of an electron beam. There is a disadvantage that the time required for display increases as the number of displays increases. On the other hand, the latter receives coordinate signals at both ends of a number of line segments that form a character to be displayed, and sequentially generates vectors of two consecutive coordinate signals by a vector generator. For example, a bright line group by an electron beam of a cathode ray tube display device. This is a display method, and has the drawbacks that the display speed is limited and the cost is high because it requires vector generation including an integrator, for example.

When a device for displaying character information together with a waveform on a cathode ray tube is constructed by combining a character signal generator according to the above two methods and a waveform observing device such as an oscilloscope, a screen display example in the former raster scanning method Ten
Shown in the figure. The shaded circles ○ are the bright spots during lighting, and the ○ marks are the bright spots during lighting. In this way, the ratio of bright points to the number of scanning points is small, and when characters and waveforms are alternately switched and displayed, scanning points other than bright points must also be scanned, resulting in low display efficiency. . Further, in any of the above methods, the waveform display must be interrupted during the time during which the characters are displayed, so there is a drawback that the waveform displayed on the tube surface is partially lost depending on the horizontal sweep speed. there were. In the case of Fig. 10, the display efficiency can be expressed by the following formula.

Conventionally, a method of drawing characters at high speed has been used to eliminate the above drawbacks, but expensive components must be used, and the circuit configuration tends to be complicated.

(Object) To solve the above-mentioned drawbacks, a character display circuit suitable for an oscilloscope in which the waveform is not partially omitted even when the waveform and the character are simultaneously displayed on the tube surface by using inexpensive parts. Is to provide.

(Embodiment) In the present invention, in a device configured to alternately display a waveform and a character in a constant cycle, when a character display state is set, a time other than a bright point forming a character is displayed on the tube surface. Paying attention to the fact that nothing is displayed, the waveform and character display switching efficiency was improved by switching from waveform display to character display only at the bright spots that compose a character. Further, by the above switching method, when the waveform and the character are displayed at the same time, the lack of the waveform which occurs when the speed of the character display and the sweep speed of the waveform are in an integral multiple is inconspicuous.

The present invention will be described below with reference to the block diagram shown in FIG. A signal input terminal 1 is connected to a vertical axis waveform / character switching circuit 3 and a trigger generation circuit 5 via a vertical axis amplifier circuit 2. The waveform / character switching circuit 3 is connected to the vertical deflection plate of the cathode ray tube 11 via the vertical axis output circuit 4. The trigger generation circuit 5 is connected to the Z-axis output circuit 10 via the Z-axis waveform / character switching circuit 9, and further the Z-axis output circuit
The output of 10 is connected to the cathode ray tube 11. The trigger generation circuit 5 is connected to the sweep signal generation circuit 6, and its output is output via the horizontal axis waveform / character switching circuit 7 to the horizontal axis output circuit 8
The output of the horizontal axis output circuit 8 is connected to the horizontal deflection plate of the cathode ray tube 11. The sweep end signal from the sweep signal generation circuit 6 is connected to the trigger generation circuit 5 and the character display control circuit 12, and the character display control circuit 12 is connected to the character signal generation circuit 13. The character signal generation circuit 13 includes a vertical axis waveform / character switching circuit 3, a horizontal axis waveform / character switching circuit 7,
It is connected to the Z-axis waveform / character switching circuit 9.

The character signal generating circuit 13 outputs the waveform shown in FIG. 3 when the character shown in FIG. 2 is drawn on the cathode ray tube. The X-axis and Y-axis signals shown in FIG. 3 are signals for performing sequential scanning like a television scanning line. The Y-axis signal is the vertical axis waveform / character switching circuit 3, and the X-axis signal is respectively. It is applied to the horizontal axis waveform / character switching circuit 7. Also, the third
The Z-axis signal shown in the figure is a signal for bending the tube surface when the X-axis signal and the Y-axis signal come to the position of the bright spot forming a character.

Vertical / horizontal and Z-axis waveform / character switching circuit 3,7,9
Is normally on the waveform side by the character display control circuit 12, that is, the vertical axis waveform / character switching circuit 3 connects the signal applied to the input terminal 1 to the vertical axis output circuit 4 via the vertical axis amplifier circuit 2. The horizontal axis waveform / character switching circuit 7 also connects the signal from the sweep signal generation circuit 6 to the horizontal axis output circuit 8. Similarly, the Z-axis waveform / character switching circuit 9 also connects the Z-axis signal from the trigger generation circuit 5 to the Z-axis output circuit 10. At this time, when the X-axis and Y-axis signals of the character display come to the bright spot position forming the character, the character display control circuit 12
Upon receiving the signal from the character signal generation circuit 13, it outputs a switching control signal to the waveform / character switching circuits 3, 7, 9. Receiving this, the waveform / character switching circuits 3, 7, 9 are respectively for the Y signal, X signal, and
The Z axis signal is applied to the vertical axis output circuit 4, the horizontal axis output circuit 8, and the Z axis output circuit 10. Further, when the X-axis and Y-axis signals of the character display have finished passing through the bright spots forming the character, the character display control circuit 12 switches the waveform / character switching circuits 3, 7, 9 from the character side to the waveform side.

By performing the operations described above, waveforms and characters can be displayed simultaneously.

Next, a detailed circuit and operation description of each block shown in FIG. 1 will be described. Among the blocks shown in FIG. 1, the vertical axis amplification circuit 2, vertical axis output circuit 4, trigger generation circuit 5, sweep signal generation circuit 6, horizontal axis output circuit 8, Z axis output circuit 10, and cathode ray tube 11 are conventional. The circuit is the same as that used in the oscilloscope, and detailed circuit description is omitted.

The detailed circuit of the vertical axis waveform / character switching circuit 3 is shown in FIG.
The detailed circuit of the horizontal axis waveform / character switching circuit 7 is shown in FIG.
FIG. 6 shows a Z-axis waveform / character switching circuit 9, and FIG. 7 shows a character display control circuit 12 and a character signal generation circuit 13.

In the vertical axis waveform / character switching circuit 3 of FIG. 4, the anodes of the diodes 14a, 14b, 14c, 14d are connected to the differential output of the vertical axis amplifier circuit 2, and the cathode of the diode 14a is the base of the transistor 15. The cathode of the diode 14b is connected to the base of the transistor 16. The cathodes of the diodes 14c and 14d are both connected to the waveform / character switching signal from the character display control circuit 12. diode
The anode of 30a, 30b, 30c, 30d is the power source + via the resistors 90, 91
Connected to V, the cathodes of the diodes 30a and 30c are connected to the bases of the transistors 15 and 16, and the cathodes of the diodes 30d and 30b are connected to the waveform of the character display control circuit 12 via the inverter 31.
It is connected to the character switching signal. The emitters of the transistors 15 and 16 are connected to the power supply -V via resistors 17 and 18, respectively, and the emitters are connected via a resistor 19. The collectors of transistors 15 and 16 are connected to the emitters of transistors 20 and 21, respectively.
The bases are connected to each other, and the connection point is connected to the ground level and the power supply + V via the resistors 23 and 22. The collectors of the transistors 20 and 21 are connected to the power source + V via resistors 27 and 26, respectively, and are also connected to the collector of the transistor 37 via resistors 24 and 25. Further, the collectors of the transistors 20 and 21 are connected to the input terminal of the vertical axis output amplifier circuit 4 and also connected to the collectors of the transistors 32 and 33 via resistors 28 and 29, respectively. The emitters of the transistors 32 and 33 are connected to each other via the resistor 35, and are also connected to the collector of the transistor 38 via the resistors 34 and 36. The base of the transistor 32 is grounded, and the base of the transistor 33 is applied with the vertical axis signal of the character from the character signal generation circuit 13. Transistor 38
This base is grounded to the ground level and the power supply -V via resistors 39 and 40. The base of the transistor 37 is connected to the waveform / character switching signal from the character display control circuit 12, and the emitters of the transistors 37 and 38 are connected to the power supply -V via the resistor 41.

In the above connection, the waveform from the character display control circuit 12
The character switching signal is on the waveform side (tentatively "high")
At this time, since the diodes 14c and 14d are in the reverse bias state,
The output from the vertical axis amplifier circuit 2 is applied to the bases of the transistors 15 and 16 via the diodes 14a and 14b. At this time, the transistor 1 passes through the diodes 30a, 30c resistors 90, 91.
The current flowing into the bases of 5 and 16 does not flow because it flows into the inverter 31 via the diodes 30d and 30b (because the output of the inverter 31 becomes "low"). Resistors 17, 18 and 1
9 determines the operating point and the gain of the transistors 15 and 16. The signals applied to the transistors 15 and 16 via the diodes 14a and 14b are amplified by the transistors 15 and 16 and applied to the vertical axis output amplifier circuit 4 via the base ground type amplifier circuit composed of the transistors 20 and 21. It The resistance
22 and 23 determine the operating points of the transistors 20 and 21. At this time, the voltage applied to the vertical axis output amplifier circuit 4 has an amplitude determined by the resistors 26 and 27 and the resistors 25 and 24 because the transistor 37 is in the operating state. The transistors 37 and 38 form a current switch.
In the operating state, the transistor 38 is inactive, so the differential amplifier formed by the transistors 32 and 33 does not operate, and the character signal from the character signal generating circuit 13 is not applied to the vertical axis output amplifying circuit 4. Therefore, when the waveform / character switching signal from the character display control circuit 12 is “high” (on the waveform side), the output of the vertical axis amplifier circuit 2 is applied to the output amplifier circuit 4,
A waveform is drawn on the cathode ray tube 11.

Next, on the character display side, the waveform / character switching signal is "low".
The output of the vertical axis amplification circuit 2 is diodes 14c and 14d.
It will be bypassed through and will not be applied to the bases of transistors 15 and 16. In order to stabilize the operating points of the transistors 15 and 16, resistors 90 and 91, diodes 30a and 30
The bases of the transistors 15 and 16 are connected to the power supply + V via c. Therefore, the transistors 15, 16, 20, 21 are fixed at a certain operating point. At this time, the transistor 37 is in the non-operating state and the transistor 38 is in the operating state.
The differential amplifier constituted by the transistors 32 and 33 operates, and the character signal output from the character signal generation circuit 13 is applied to the vertical axis output amplification circuit 4 via the transistors 33 and 32 and the resistors 29 and 28. The signal level at this time is determined by the resistors 36, 35 and 34. Therefore, when the waveform / character switching signal is "low", a character signal is applied on the cathode ray tube 11 to draw a character. Next, in the horizontal axis waveform / character switching circuit of FIG. 5, the bases of the transistors 42 and 43 are connected to the differential outputs of the sweep signal generating circuit 6, and the collectors thereof are horizontal with the collectors of the transistors 47 and 48. It is connected to the input side of the shaft output amplifier circuit 8. Transistors 42,4
The emitter of 3 is connected to the collector of the transistor 53 via resistors 44 and 45, respectively, and the emitters of the transistors 42 and 43 are connected to each other via a resistor 46. The base of the transistor 47 is connected to the character signal generation circuit 13, and the base of the transistor 48 is grounded. The emitters of the transistors 47 and 48 are connected to the collector of the transistor 52 via resistors 49 and 50, respectively, and the emitters of the transistors 47 and 48 are connected to each other via a resistor 51. The base of the transistor 53 is connected to the waveform / character switching signal of the character display control circuit 12, and the base of the transistor 52 is connected to the power source + V and the ground level via the resistors 54 and 55. The emitters of the transistors 52 and 53 are connected to each other, and both are connected to the power supply -V via the resistor 56.

In the above connection, the waveform from the character display control circuit 12
When the character switching signal is on the waveform side (probably "high"), the current switch composed of transistors 52 and 53 is in the operating state on the side of transistor 53, so the emitter currents of transistors 42 and 43 pass through resistors 44 and 45. And the output of the sweep signal generation circuit 6 is connected to the horizontal axis output amplification circuit 8 via the transistors 42 and 43. In addition, transistors 47, 48
Does not operate because transistor 52 is inactive.

Next, when the waveform / character switching signal of the character display control circuit 12 is on the character side (probably "low"), the transistor 52 is in the operating state, so that the character signal from the character signal generation circuit 13 is the transistor 47, It is connected to the horizontal axis output amplification circuit 8 via 48. At this time, since the transistor 53 is in the non-operating state, the transistors 42 and 43 do not operate. Therefore,
The output of the sweep signal generation circuit 6 is not connected to the horizontal axis output amplification circuit 8.

As described above, the control signal from the character display control circuit 12 switches the waveform and characters on the horizontal axis.

Next, switching between the Z-axis waveform and characters will be described with reference to FIG. In FIG. 6, one input of the logic element 58 is connected to the trigger generation circuit 5, and the other input is connected to the waveform / character switching signal of the character display control circuit 12. The output of the logic element 58 is connected to the control terminal of the switch element 62. The switch element 62 is the same as the logic element 58.
Closes when the output of is low and opens when it is high. One end of the switch element 62 is connected to the ground level and the power supply -V via the variable resistor 61. Further, the waveform / character switching signal from the character display control circuit 12 is connected to one input of the logic element 59 via the inverter 57, and the other input of the logic element 59 is connected to the Z of the character from the character signal generation circuit 13. It is connected to the axis signal. The output of the logic element 59 is connected to the control signal of the switch element 63. The switch element 63 is the logic element 59.
Closes when the output of is low and opens when it is high. The signal terminal of the switch element 63 is connected to the ground level and the power supply -V via the variable resistor 60. Further, the other signal terminals of the switch element 62 and the switch element 63 are both connected to the Z-axis output circuit 10.

In the above connection, the waveform from the character display control circuit 12
When the character switching signal is on the character side (probably "high"), the logic element 58 (nand gate in this embodiment) sets the output to "low" according to the output of the trigger generation circuit 5, and the switch element 62 Close and set to the operating state. At this time, the voltage value determined by the variable resistor 61 is transmitted to the Z-axis output circuit 10. At this time, the output of one logic element 59 (the NAND gate in this embodiment) does not become "low" because of the output of the inverter 57. Therefore, the switch element 63 is in the open state, that is, in the non-operating state, and the value determined by the variable resistor 60 is not transmitted to the Z-axis output amplifier circuit 10.

Next, when the waveform / character switching signal is on the character side (probably "low")
In contrast to the above-mentioned operation, the logic element 59 is activated and the voltage value determined by the variable resistor 60 is the Z-axis output circuit.
Applied to 10. Here, the voltage values determined by the variable resistors 60 and 61 correspond to the brightness of the characters and the waveform on the cathode ray tube, respectively. As described above, the Z-axis can alternately switch between the character and the waveform state by the waveform / character switching signal.

FIG. 7 shows detailed circuits of the character display control circuit 12 and the character signal generation circuit 13. The output of the clock generation circuit 81 is connected to the binary counter 80, the logic element 76, and the shift register 75.

The output of the binary counter 80 is the memory for character patterns 79,
Character horizontal axis D / A converter 82 and character vertical axis D / A converter
One of the outputs of the counter is connected to 83, and the output of one of the counters is connected to the integrator composed of the amplifier 92, the capacitor 64, and the resistors 65 and 66 via the retriggerable one-shot multi 93 and the resistor 67. Has been done. The output of the character pattern memory 79 is connected to the data selector 78, and the output of the data selector 78 is connected to one input terminal of the logic element 76. The output of the one-shot multi 72 and the shift register 75 are respectively connected to the two remaining input terminals of the logic element 76.
The output of the logic element 76 is connected to the output of the shift register
It is connected to the reset terminal of 75. Shift register 75
Q _A and Q _D are respectively connected to the logic element 74, and the output of the logic element 74 is used as a waveform / character switching signal for X, Y, and
It is connected to the Z waveform character switching circuit 3, 9, 7. Also,
Q _B and Q _C are connected to the logic element 73, and the output of the logic element 73 is
As a character Z-axis signal, it is connected to the Z-axis waveform / character switching circuit 9 and also to the trigger terminal of the one-shot multi 72. The output of the D / A converter 82 is connected to the X-axis waveform / character switching circuit 7 as a character X-axis signal.
The output of the converter 83 is connected to the Y-axis waveform / character switching circuit 3 as a character Y-axis signal. The output of the aforementioned amplifier 92 is connected to the base of the transistor 70 via the resistor 68, and the collector of the transistor 70 is connected to the capacitor 71 and the one-shot multi 72. The output of the sweep signal generation circuit 6 is also connected to the transistor 70 via the resistor 69.

In the above connection, the binary counter 80 counts according to the output of the clock generation circuit 81, and its output is D /
The A converters 82 and 83 output the characters as X-axis and Y-axis signals. At the same time, the output of the counter 80 selects a character pattern from the character pattern memory 79 and outputs it to the data selector 78. The data selector 78 parallel-serial converts the data sent from the memory 79 and outputs the data to the logic element 76. The logic element 76 resets the shift register 75 at the timing when the outputs of the clock generation circuit 81, the shift register 75, and the one-shot 72 match. At this time, the output of the data selector 78 is "high" (corresponding to the bright spot). The reset shift register 75 has Q _A , Q _B , Q _C , Q _D ,
Shift data in the order of Q _E. Logic element 74 is Q _A to Q _D
The waveform / character switching signal is set to the character state while the data is being shifted to. Further, the logic element 73 outputs the Z-axis signal of the character between Q _B and Q _C. At this time, the Z-axis signal of the character accesses the one-shot multi 72, the one-shot multi 72 controls the logic element 76 for a time determined by the current flowing through the capacitor 71 and the transistor 70, and prohibits the reset of the shift register 75. Therefore, even if the bright spot pattern is continuously sent from the data selector 78, a certain prohibited time can be set. Further, when the data selector 78 is outputting a bright spot (“high”), it controls the binary counter 80 to stop counting at the same time when the bright spot is outputted.
On the other hand, when the shift register 75 sends data to Q _E ,
The output of the data selector 78 is prohibited. As a result, the binary counter 80 counts again. As described above, the binary counter 80 performs high-speed counting except for the bright spot, and stops counting at the bright spot until the shift register 75 finishes shifting. When the bright spots are continuous, the operation is stopped for the time determined by the one-shot multi 72. The one-shot multi-72 determines the one-shot time by the current determined by the transistor 70, and this time is determined by the integrated voltage of the integrator composed of the capacitor 64, the amplifier 92, and the resistors 65 and 66. Since the integrator described above performs integration based on the result of one shot of one output of the binary counter 80, the integration voltage is low when the counting is performed at high speed, and the integration voltage is increased when the counting is performed at low speed. Therefore, when the count is high, the current flowing through the transistor 70 is small and the one-shot time is long. Further, when the count is low, the current flowing through the transistor 70 becomes large, and the one-shot time becomes short. By the above operation, a constant screen display speed can be secured even when there are many bright spots forming a character.

FIG. 8 shows a display example of the waveform and characters displayed on the cathode ray tube, where 84 is the displayed waveform and 90 is the displayed character.
Further, FIG. 9 shows the CRT driving signals of the X-axis signal, the Y-axis signal and the Z-axis signal at that time.

In FIG. 9, the measured input signal waveform 84 is alternately switched on the Y axis with the character Y axis signal 85. Similarly, for the X-axis, the sweep signal 86 is switched to the character X-axis signal 87, and the Z-axis signal is alternately switched to the sweep luminance signal 89 and the character luminance signal 88.

(Effect) In the displayable oscilloscope according to the present invention, the switching from the waveform to the character does not occur except at the bright spots forming the character, so that the waveform is not largely lost. Moreover, the brightness forming the characters can be regarded as being relatively random, and the same portion on the displayed waveform is not always missing, so stable waveform observation is possible.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a diagram showing an example of characters drawn on a cathode ray tube, FIG. 3 is an output waveform diagram of a character signal generating circuit in an embodiment of the present invention, and FIG. FIG. 5 is a circuit diagram of a vertical axis waveform / character switching circuit in the embodiment of the present invention, and FIG. 5 is a horizontal axis waveform / character switching circuit in the embodiment of the present invention.
6 is a circuit diagram of the character switching circuit, FIG. 6 is a circuit diagram of the Z-axis waveform character switching circuit in the embodiment of the present invention, and FIG. 7 is a circuit diagram of the character display control and character signal generating circuit in the embodiment of the present invention. FIG. 8 is a diagram showing an example of characters and waveforms drawn on a cathode ray tube, FIG. 9 is a Y-axis, X-axis, and Z-axis signal waveform diagram in the present invention, and FIG. 10 is an example of display of a cathode ray tube screen in a raster scanning system. FIG. 1: Input terminal, 2: Vertical axis amplification circuit, 3: Vertical axis waveform / character switching circuit, 4: Vertical axis output circuit, 5: Trigger control circuit, 6: Sweep signal generation circuit, 7: Horizontal axis waveform character Switching circuit, 8: Horizontal axis output circuit, 9: Z axis waveform / character switching circuit, 10: Z axis output circuit, 11:
CRT, 12: Character display control circuit, 13: Character signal generation circuit.

Claims (1)

[Claims] 1. An oscilloscope comprising means for storing coordinates of bright spot dots forming a character on a display screen, reading means for sequentially reading the dots from the storage means, and reading of characters from the reading means. The control means for controlling the display screen to switch from the waveform to the character only when the position of the bright spot dot forming the character is reached, the means for detecting the frequency of occurrence of the bright spot dot, and the bright means according to the output of the detecting means. An oscilloscope having a read speed control means for controlling the read means such that the read speed of the storage means is reduced when the dot dot occurrence frequency is high and the read speed is increased when the dot dot occurrence frequency is low.