Modulation unit automatic detection circuit

Abstract

The utility model discloses an automatic detection circuit for a modulation unit, which belongs to the technical field of modulation unit detection, and comprises a voltage indicating circuit and an overvoltage and undervoltage indicating circuit, the modulation unit comprises a positive bias voltage, a grid voltage and a filament voltage of a traveling wave tube and a filament voltage of a modulation tube, the voltage indicating circuit comprises K1 and CB1, a contact 1 of the K1 is connected with a positive electrode of a + 48V power supply, a contact 2 is connected with a positive electrode of an output end of the conversion isolation module 1, a contact 3 is connected with a positive electrode of an output end of the conversion isolation module 2, a contact 4 is connected with a positive electrode of a + 15V power supply, contacts 5, 6, 7 and 8 are connected in parallel and then are connected with one end of the voltage check meter CB1, and the other end of the CB1 is grounded. The over-voltage and under-voltage indicating circuit comprises a + 6V power supply module, a sampling circuit, a comparison circuit, a driving circuit and an alarm indicating circuit, a detection circuit can be designed according to the circuit structure of the modulation unit to achieve the purpose of autonomous maintenance, and meanwhile, the modulation unit can be detected in time to achieve a preventive maintenance effect.

Description

Technical Field

[0001] The utility model relates to the technical field of modulation unit detection, and more specifically, to an automatic detection circuit for a modulation unit. Background Art

[0002] The modulation unit is a key link in the traveling wave tube circuit of some devices. When a fault occurs or the voltage parameter exceeds the rated range, it is extremely easy to cause the traveling wave tube to strike an arc, and even cause damage to the traveling wave tube. Therefore, it is particularly necessary to check the status of the modulation unit before the traveling wave tube works. During the use of the device in recent years, the modulation unit has failed many times, seriously affecting the reliability of the traveling wave tube operation and reducing the service life of the traveling wave tube to a certain extent.

[0003] Since the modulation unit works in a high-voltage environment and there is no corresponding detection port, it can only be repaired by returning to the factory after a failure. Therefore, there is an urgent need for an automatic detection circuit for a modulation unit to solve the above problems. Summary of the Utility Model

[0004] 1. Technical Problems to be Solved

[0005] Aiming at the problems existing in the prior art, the purpose of the utility model is to provide an automatic detection circuit for a modulation unit, which can design a detection circuit according to the circuit structure of the modulation unit to achieve the purpose of autonomous maintenance, and can also detect the modulation unit in a timely manner to achieve the effect of preventive maintenance.

[0006] 2. Technical Solutions

[0007] To solve the above problems, the utility model adopts the following technical solutions.

[0008] An automatic detection circuit for a modulation unit includes a voltage indication circuit and an over-voltage and under-voltage indication circuit. The modulation unit includes the positive bias voltage, grid voltage, filament voltage for the traveling wave tube, and the filament voltage of the modulation tube. The voltage indication circuit includes a multi-position switch K1 and a voltage inspection table CB1. The contact 1 of the multi-position switch K1 is connected to the positive pole of the +48V power supply, the contact 2 is connected to the positive pole of the output of the conversion isolation module 1, the contact 3 is connected to the positive pole of the output of the conversion isolation module 2, the contact 4 is connected to the positive pole of the +15V power supply, the contacts 5, 6, 7, and 8 are connected in parallel and then connected to one end of the voltage inspection table CB1, and the other end of the voltage inspection table CB1 is grounded. The over-voltage and under-voltage indication circuit includes a +6V power supply module, a sampling circuit, a comparison circuit, a driving circuit, and an alarm indication circuit.

[0009] Further, the filament voltage is provided by a +15V power supply. After passing through the conversion isolation module 1, a +12V voltage is output to supply power to the traveling wave tube filament, and after passing through the conversion isolation module 2, a +9V voltage is output to supply power to the modulator filament. The positive bias voltage and the grid voltage of the traveling wave tube are provided by a +48V power supply. The adjustment range of the positive bias voltage is between +350V and +450V and is controlled by W1. The adjustment range of the grid voltage is +380V to +420V and is controlled by W2.

[0010] Further, the sampling circuit consists of resistors R1 (1W 100K), R2 (1W 1K) and R1' (1W 100K), R2' (1W 1K). Among them, R1 and R2 are the positive bias voltage sampling circuits. One end of R1 is connected to the output end of the positive bias voltage, the other end of R1 is connected to one end of R2, and the other end of R2 is grounded. The positive bias voltage sampling is taken out from the connection end of R1 and R2 and sent to pins 5 and 6 of the voltage comparator IC1. When the positive bias voltage is within the rated range of +350V to +450V, the sampling voltage range is +3.5V to +4.5V; R1' and R2' are the grid voltage sampling circuits. One end of R1' is connected to the output end of the grid voltage, the other end of R1' is connected to one end of R2', and the other end of R2' is grounded. The grid voltage sampling is taken out from the connection end of R1' and R2' and sent to pins 9 and 10 of the voltage comparator IC1. When the grid voltage is within the rated range of +380V to +420V, the sampling voltage range is +3.8V to +4.2V.

[0011] Further, the comparison circuit consists of IC1 and resistors R3 (0.5W 1.5K), R4 (0.5W 2K), R5 (0.5W 1.5K), R6 (0.5W 4.7K) and resistors R3' (0.5W 2.7K), R4' (0.5W 4.7K), R5' (0.5W 2K), R6' (0.5W 4.7K).

[0012] Further, the IC1 is an LM339 voltage comparator chip, which contains four groups of independent voltage comparators and has 14 pins. Among them, pin 3 is the power supply terminal and pin 12 is the grounding terminal; pins 2, 4, and 5 form the first group of voltage comparator IC1:A, where pin 2 is the output terminal, pin 4 is the inverting input terminal, and pin 5 is the non-inverting input terminal; pins 1, 6, and 7 form the second group of voltage comparator IC1:B, where pin 1 is the output terminal, pin 6 is the inverting input terminal, and pin 7 is the non-inverting input terminal; pins 14, 8, and 9 form the third group of voltage comparator IC1:C, where pin 14 is the output terminal, pin 8 is the inverting input terminal, and pin 9 is the non-inverting input terminal; pins 13, 10, and 11 form the fourth group of voltage comparator IC1:D, where pin 13 is the output terminal, pin 10 is the inverting input terminal, and pin 11 is the non-inverting input terminal.

[0013] Further, the drive circuit includes U1, VT1 (transistor 9013), VT2 (transistor 9013), VT3 (transistor 9013), VT4 (transistor 9013), and R7 (0.5W 1K), R10 (0.5W 1K), R7' (0.5W 1K), R10' (0.5W 1K) are current-limiting resistors for U1, and R8 (0.5W 1K), R11 (0.5W 1K), R8' (0.5W 1K), R11' (0.5W 1K) are base resistors for VT1, VT2, VT3, and VT4 respectively.

[0014] Further, U1 includes four groups of independent 2-input NAND gates, with 14 pins. Among them, pin 14 is the power supply terminal, and pin 7 is the ground terminal; pins 1, 2, and 3 form the first group of NAND gate U1:A, where pins 1 and 2 are input terminals and pin 3 is the output terminal; pins 4, 5, and 6 form the second group of NAND gate U1:B, where pins 4 and 5 are input terminals and pin 6 is the output terminal; pins 8, 9, and 10 form the third group of NAND gate U1:C, where pins 9 and 10 are input terminals and pin 8 is the output terminal; pins 11, 12, and 13 form the fourth group of NAND gate U1:D, where pins 12 and 13 are input terminals and pin 11 is the output terminal.

[0015] Further, the alarm indication circuit includes light-emitting diodes D1 (red), D2 (red), D3 (red), D4 (red) and resistors R9 (0.5W 200Ω), R12 (0.5W 200Ω), R9' (0.5W 200Ω), R12' (0.5W 200Ω), and R9, R12, R9', R12' are current-limiting resistors for D1, D2, D3, and D4 respectively.

[0016] 3. Beneficial Effects

[0017] (1) This detection circuit can monitor the modulation unit in real time, playing a preventive maintenance function and solving the problem that such faults can only rely on the manufacturer for guarantee.

[0018] (2) This detection circuit is simple to operate and convenient to use. According to different status indications, the fault can be accurately compressed to a specific module, and the maintenance efficiency is increased by 60%.

[0019] (3) The sampling circuit of this detection circuit is ingeniously designed, greatly improving the maintenance safety. Description of the Drawings

[0020] Figure 1 It is a block diagram of the modulation unit of the present utility model;

[0021] Figure 2 It is a block diagram of the voltage indication circuit of the present utility model;

[0022] Figure 3 It is the block diagram of the over- and under-voltage indication circuit of the present utility model;

[0023] Figure 4 It is the circuit diagram of the voltage indication of the present utility model;

[0024] Figure 5 It is the circuit diagram of the over- and under-voltage indication of the present utility model;

[0025] Figure 6 It is the circuit diagram of the automatic detection of the modulation unit of the present utility model;

[0026] Figure 7 It is the truth table of the 74LS00 NAND gate of the present utility model;

[0027] Figure 8 It is the inspection and debugging table of the modulation unit of the present utility model. Specific implementation manners

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model; obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0029] Embodiment 1:

[0030] Please refer to Figure 1 , the modulation unit mainly provides the positive bias voltage, grid voltage, filament voltage for the traveling wave tube to work, and the filament voltage for the modulation tube. Among them, the filament voltage is provided by the +15V power supply, and after passing through the conversion and isolation module 1, +12V voltage is output to supply power to the traveling wave tube filament; after passing through the conversion and isolation module 2, +9V voltage is output to supply power to the modulator filament. The positive bias voltage and grid voltage of the traveling wave tube are provided by the +48V power supply. Affected by the traveling wave tube process, the optimal positive bias voltage and grid voltage of different tubes are slightly different. Therefore, there is a certain adjustment range for these two voltages. Among them, the adjustment range of the positive bias voltage is between +350V and +450V, controlled by W1; the adjustment range of the grid voltage is +380V to +420V, controlled by W2.

[0031] Please refer to Figures 2-3 , the automatic detection circuit design includes a voltage indication circuit and an over- and under-voltage indication circuit. Among them, the voltage indication circuit includes the traveling wave tube filament voltage indication, the modulator filament voltage indication, and the +48V and +15V input power supply indications, which are realized by the direct detection method. The over- and under-voltage indication circuit includes the over- and under-voltage indications of the positive bias voltage and the grid voltage, which are realized by the sampling and comparison method.

[0032] Please refer toFigure 4 The voltage indication circuit mainly draws out the input power supplies of +48V and +15V, as well as the filament voltages of the traveling wave tube and the modulator, and visually displays them on the voltmeter through a change-over switch. The multi-position switch K1 is a multi-position switch. Contact 1 is connected to the positive pole of the +48V power supply, contact 2 is connected to the positive pole of the output of conversion isolation module 1, contact 3 is connected to the positive pole of the output of conversion isolation module 2, contact 4 is connected to the positive pole of the +15V power supply, and contacts 5, 6, 7, and 8 are connected in parallel and then connected to one end of the voltage inspection table CB1. The other end of the voltage inspection table CB1 is grounded. The range of the voltage inspection table CB1 is 50V DC.

[0033] Please refer to Figure 5 The over- and under-voltage indication circuit mainly checks the over- and under-voltage conditions of the positive bias voltage and the grid voltage. When the positive bias voltage and the grid voltage work within a reasonable range, the warning indicator light does not light up, and the device can proceed to the next step; when the positive bias voltage or the grid voltage has over-voltage or under-voltage, the corresponding warning indicator light is lit, reminding the operator not to allow the next step of operation. At this time, the corresponding potentiometer should be adjusted to make the output voltage meet the index requirements.

[0034] The +6V power supply module is powered by 50Hz 220V and outputs +6V DC voltage to provide the working voltage for the circuit.

[0035] The sampling circuit consists of resistors R1 (1W 100K), R2 (1W 1K), R1' (1W 100K), and R2' (1W 1K). Among them, R1 and R2 are the positive bias voltage sampling circuits. One end of R1 is connected to the output end of the positive bias voltage, the other end of R1 is connected to one end of R2, and the other end of R2 is grounded. The positive bias voltage sampling is taken out from the connection end of R1 and R2 and sent to pins 5 and 6 of the voltage comparator IC1. When the positive bias voltage is within the rated range of +350V to +450V, the sampling voltage range is +3.5V to +4.5V; R1' and R2' are the grid voltage sampling circuits. One end of R1' is connected to the output end of the grid voltage, the other end of R1' is connected to one end of R2', and the other end of R2' is grounded. The grid voltage sampling is taken out from the connection end of R1' and R2' and sent to pins 9 and 10 of the voltage comparator IC1. When the grid voltage is within the rated range of +380V to +420V, the sampling voltage range is +3.8V to +4.2V.

[0036] IC1 is an LM339 voltage comparator chip, powered by a +6V power supply. This comparator chip contains four independent voltage comparators and has 14 pins. Among them, pin 3 is the power supply terminal, and pin 12 is the ground terminal; pins 2, 4, and 5 form the first group of voltage comparator IC1:A, where pin 2 is the output terminal, pin 4 is the inverting input terminal, and pin 5 is the non-inverting input terminal; pins 1, 6, and 7 form the second group of voltage comparator IC1:B, where pin 1 is the output terminal, pin 6 is the inverting input terminal, and pin 7 is the non-inverting input terminal; pins 14, 8, and 9 form the third group of voltage comparator IC1:C, where pin 14 is the output terminal, pin 8 is the inverting input terminal, and pin 9 is the non-inverting input terminal; pins 13, 10, and 11 form the fourth group of voltage comparator IC1:D, where pin 13 is the output terminal, pin 10 is the inverting input terminal, and pin 11 is the non-inverting input terminal.

[0037] IC1 and resistors R3 (0.5W 1.5K), R4 (0.5W 2K), R5 (0.5W 1.5K), R6 (0.5W 4.7K) and resistors R3' (0.5W 2.7K), R4' (0.5W 4.7K), R5' (0.5W 2K), R6' (0.5W 4.7K) together form a comparison circuit. Among them, resistors R3 and R4 provide a +3.5V reference voltage for IC1:A. When the sampled voltage is greater than the reference voltage, IC1:A outputs a high level; when the sampled voltage is less than the reference voltage, IC1:A outputs a low level; resistors R5 and R6 provide a +4.5V reference voltage for IC1:B. When the sampled voltage is less than the reference voltage, IC1:B outputs a high level; when the sampled voltage is greater than the reference voltage, IC1:B outputs a low level; resistors R3' and R4' provide a +3.8V reference voltage for IC1:C. When the sampled voltage is greater than the reference voltage, IC1:C outputs a high level; when the sampled voltage is less than the reference voltage, IC1:C outputs a low level; resistors R5' and R6' provide a +4.2V reference voltage for IC1:D. When the sampled voltage is less than the reference voltage, IC1:D outputs a high level; when the sampled voltage is greater than the reference voltage, IC1:D outputs a low level.

[0038] U1 is a 74LS00 NAND gate chip, powered by a +6V power supply. This NAND gate chip contains four independent 2-input NAND gates and has 14 pins. Among them, pin 14 is the power supply terminal, and pin 7 is the ground terminal; pins 1, 2, and 3 form the first group of NAND gate U1:A, where pins 1 and 2 are the input terminals, and pin 3 is the output terminal; pins 4, 5, and 6 form the second group of NAND gate U1:B, where pins 4 and 5 are the input terminals, and pin 6 is the output terminal; pins 8, 9, and 10 form the third group of NAND gate U1:C, where pins 9 and 10 are the input terminals, and pin 8 is the output terminal; pins 11, 12, and 13 form the fourth group of NAND gate U1:D, where pins 12 and 13 are the input terminals, and pin 11 is the output terminal.

[0039] U1, VT1 (transistor 9013), VT2 (transistor 9013), VT3 (transistor 9013), and VT4 (transistor 9013) form a drive circuit. When the output of IC1:A is high, the output of U1:A is low and VT1 is cut off; when the output of IC1:A is low, the output of U1:A is high and VT1 is turned on. When the output of IC1:B is high, the output of U1:B is low and VT2 is cut off; when the output of IC1:B is low, the output of U1:B is high and VT2 is turned on. When the output of IC1:C is high, the output of U1:C is low and VT3 is cut off; when the output of IC1:C is low, the output of U1:C is high and VT3 is turned on. When the output of IC1:D is high, the output of U1:D is low and VT4 is cut off; when the output of IC1:D is low, the output of U1:D is high and VT4 is turned on.

[0040] R7 (0.5W 1K), R10 (0.5W 1K), R7' (0.5W 1K), and R10' (0.5W 1K) are current-limiting resistors for U1, and R8 (0.5W 1K), R11 (0.5W 1K), R8' (0.5W 1K), and R11' (0.5W 1K) are the base resistors for VT1, VT2, VT3, and VT4 respectively.

[0041] Light-emitting diodes D1 (red), D2 (red), D3 (red), D4 (red) and resistors R9 (0.5W 200Ω), R12 (0.5W 200Ω), R9' (0.5W 200Ω), R12' (0.5W 200Ω) together form an alarm indication circuit. Among them, D1 is the under-voltage indicator for the forward bias voltage. When the forward bias voltage is lower than +350V, the output of IC1:A is low, the output of U1:A is high, VT1 is turned on, and D1 is lit by +VCC through R9 and VT1; D2 is the over-voltage indicator for the forward bias voltage. When the forward bias voltage is higher than +450V, the output of IC1:B is low, the output of U1:A is high, VT2 is turned on, and D2 is lit by +VCC through R12 and VT2; D3 is the under-voltage indicator for the gate voltage. When the gate voltage is lower than +380V, the output of IC1:C is low, the output of U1:C is high, VT3 is turned on, and D3 is lit by +VCC through R9' and VT3; D4 is the over-voltage indicator for the gate voltage. When the gate voltage is higher than +420V, the output of IC1:D is low, the output of U1:D is high, VT4 is turned on, and D4 is lit by +VCC through R12' and VT4.

[0042] R9, R12, R9', and R12' are the current-limiting resistors for D1, D2, D3, and D4 respectively.

[0043] The specific detection method is as follows: After the device modulation unit is powered on and before the traveling wave tube works, first check the +48V, +15V input voltages and the traveling wave tube and modulator filament voltages through the multi-position switch K1. The voltage inspection table CB1 should indicate 48V, 15V, 12V, and 9V respectively, and the allowable error of the four-way voltage indication is ±0.5V. If the +48V and +15V input voltage indications are not within the rated range, check the +48V and +15V power modules in the device power distribution cabinet; if the traveling wave tube and modulator filament voltage indications are not within the rated range, replace the conversion isolation module 1 and the conversion isolation module 2 respectively.

[0044] Since the positive bias voltage and the grid voltage are medium and high voltages, the daily inspection mainly relies on the over- and under-voltage warning circuit. When any warning indicator light is on, the next operation is strictly prohibited. The operator can adjust the corresponding potentiometer according to the warning indication to make the warning phenomenon disappear. At the same time, the voltage should also be measured actually and adjusted to the nominal value.

[0045] The above is only the preferred specific implementation mode of the present utility model; however, the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution of the present utility model and its improved concept, makes equivalent replacements or changes, and should be covered by the protection scope of the present utility model.

Claims

1. An automatic detection circuit for a modulation unit, characterized in that: It includes a voltage indication circuit and an over- and under-voltage indication circuit. The modulation unit includes the positive bias voltage for the traveling wave tube, the grid voltage, the filament voltage of the traveling wave tube, and the filament voltage of the modulation tube. The voltage indication circuit includes a multi-position switch K1 and a voltage inspection table CB1. The contact 1 of the multi-position switch K1 is connected to the positive pole of the +48V power supply, the contact 2 is connected to the positive pole of the output end of the conversion isolation module 1, the contact 3 is connected to the positive pole of the output end of the conversion isolation module 2, the contact 4 is connected to the positive pole of the +15V power supply, the contacts 5, 6, 7, and 8 are connected in parallel and then connected to one end of the voltage inspection table CB1, and the other end of the voltage inspection table CB1 is grounded. The over- and under-voltage indication circuit includes a +6V power supply module, a sampling circuit, a comparison circuit, a driving circuit, and an alarm indication circuit.

2. The automatic detection circuit for a modulation unit according to claim 1, wherein: Among them, the filament voltage is provided by the +15V power supply. After passing through the conversion isolation module 1, +12V voltage is output to supply power to the filament of the traveling wave tube. After passing through the conversion isolation module 2, +9V voltage is output to supply power to the filament of the modulator. The positive bias voltage and the grid voltage of the traveling wave tube are provided by the +48V power supply. Among them, the adjustment range of the positive bias voltage is between +350V and +450V, which is controlled by W1, and the adjustment range of the grid voltage is +380V to +420V, which is controlled by W2.

3. The automatic detection circuit for a modulation unit according to claim 2, characterized in that: The sampling circuit consists of resistors R1, R2 and R1', R2'. Among them, R1 and R2 are the positive bias voltage sampling circuits. One end of R1 is connected to the output end of the positive bias voltage, the other end of R1 is connected to one end of R2, and the other end of R2 is grounded. The positive bias voltage sampling is taken out from the connection end of R1 and R2 and sent to pins 5 and 6 of the voltage comparator IC1. When the positive bias voltage is within the rated range of +350V to +450V, the sampling voltage range is +3.5V to +4.5V; R1' and R2' are the grid voltage sampling circuits. One end of R1' is connected to the output end of the grid voltage, the other end of R1' is connected to one end of R2', and the other end of R2' is grounded. The grid voltage sampling is taken out from the connection end of R1' and R2' and sent to pins 9 and 10 of the voltage comparator IC1. When the grid voltage is within the rated range of +380V to +420V, the sampling voltage range is +3.8V to +4.2V.

4. The automatic detection circuit for a modulation unit according to claim 3, wherein: The comparison circuit consists of IC1 and resistors R3, R4, R5, R6 and resistors R3', R4', R5', R6'.

5. The automatic detection circuit for a modulation unit according to claim 4, wherein: The IC1 is an LM339 voltage comparator chip, which includes four independent voltage comparators and has 14 pins. Among them, pin 3 is the power supply terminal, and pin 12 is the ground terminal; pins 2, 4, and 5 form the first group of voltage comparator IC1:A, where pin 2 is the output terminal, pin 4 is the inverting input terminal, and pin 5 is the non-inverting input terminal; pins 1, 6, and 7 form the second group of voltage comparator IC1:B, where pin 1 is the output terminal, pin 6 is the inverting input terminal, and pin 7 is the non-inverting input terminal; pins 14, 8, and 9 form the third group of voltage comparator IC1:C, where pin 14 is the output terminal, pin 8 is the inverting input terminal, and pin 9 is the non-inverting input terminal; pins 13, 10, and 11 form the fourth group of voltage comparator IC1:D, where pin 13 is the output terminal, pin 10 is the inverting input terminal, and pin 11 is the non-inverting input terminal.

6. The automatic detection circuit of a modulation unit according to claim 5, characterized in that: The drive circuit includes U1, transistors VT1, VT2, VT3, VT4. R7, R10, R7', R10' are the current-limiting resistors of U1, and R8, R11, R8', R11' are the base resistors of VT1, VT2, VT3, VT4 respectively.

7. An automatic detection circuit for a modulation unit according to claim 6, characterized in that: The U1 includes four independent 2-input NAND gates and has 14 pins. Among them, pin 14 is the power supply terminal, and pin 7 is the ground terminal; pins 1, 2, and 3 form the first group of NAND gate U1:A, where pins 1 and 2 are the input terminals and pin 3 is the output terminal; pins 4, 5, and 6 form the second group of NAND gate U1:B, where pins 4 and 5 are the input terminals and pin 6 is the output terminal; pins 8, 9, and 10 form the third group of NAND gate U1:C, where pins 9 and 10 are the input terminals and pin 8 is the output terminal; pins 11, 12, and 13 form the fourth group of NAND gate U1:D, where pins 12 and 13 are the input terminals and pin 11 is the output terminal.

8. The automatic detection circuit for a modulation unit according to claim 7, characterized in that: The alarm indication circuit includes light-emitting diodes D1, D2, D3, D4 and resistors R9, R12, R9', R12'. R9, R12, R9', R12' are the current-limiting resistors of D1, D2, D3, D4 respectively.

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