Claims
- 1. A cathode current control circuit for use with a pulsed traveling wave tube (TWT) having a cathode current, comprising:
- means for providing a comparison signal indicative of the occurrence and amplitude of a TWT cathode current pulse;
- comparing means for comparing said comparison signal with at least two predetermined reference signals indicative of a predetermined cathode current level, said comparing means for providing adjustment signals indicative of the adjustment of the TWT cathode current necesary to tend to achieve said predetermined cathode current;
- clocking means responsive to said comparison signal for providing a clock signal delayed relative to the occurrence of a cathode current pulse; and
- control means responsive to said adjustment signals and to said delayed clock signal for providing a control signal indicative of an adjusted TWT cathode current level.
- 2. The cathode current control circuit of claim 1 wherein said comparing means comprises:
- coarse adjustment comparison means responsive to said comparison signal for providing a coarse adjustment signal indicative of whether a large adjustment of the cathode current level is required; and
- fine adjustment comparison means responsive to said comparison signal for providing a fine adjustment signal indicative of whether a fine adjustment of the cathode current level is required.
- 3. The cathode current control circuit of claim 2 wherein said coarse adjustment comparison means includes a comparator responsive to said comparison signal and a first reference signal, and wherein said fine adjustment comparison means includes a comparator responsive to said comparison signal and a second reference signal.
- 4. The cathode current control circuit of claim 3 wherein said comparison signal comprises a comparison voltage, and wherein said first and second reference signals comprise first and second reference voltages.
- 5. The cathode current control circuit of claim 2 wherein said control means comprises counter circuitry which is clocked by said delayed clock signal.
- 6. The cathode current control circuit of claim 5 wherein said counter circuitry provides a substantially increased count in response to said coarse adjustment signal.
- 7. The cathode current control circuit of claim 6 wherein said counter circuitry includes a plurality of counters.
- 8. The cathode current control circuit of claim 1 wherein said clocking means includes a voltage comparator for providing a comparator output pursuant to the occurrence of a cathode current pulse, and a delay circuit responsive to said comparator output for providing a clock signal delayed relative to said comparator output.
- 9. A cathode current control circuit comprising:
- means for providing comparison signal pulses indicative of the occurrence and amplitude of cathode current pulses;
- first comparison means responsive to said comparison signal pulses for selectively providing a coarse adjust signal when a comparison signal pulse is less than a first reference signal;
- second comparison means responsive to said comparison signal pulses for providing a fine adjust signal indicative of whether a comparison signal pulse is less than a second reference signal which is greater than said first reference signal;
- clocking means responsive to said comparison signal pulses for providing clock pulses delayed relative to said comparison signal pulses; and
- counting means clocked by said delayed clock pulses and responsive to said coarse adjust signal and said fine adjust signal for providing a counter output indicative of an adjusted cathode current level.
- 10. The cathode current control circuit of claim 9 wherein said counting means provides a substantially increased counter output in response to said coarse adjust signal.
- 11. The cathode current control circuit of claim 10 wherein said fine adjust signal causes said counter output to increase when said comparison signal pulse is less than said second reference signal, or to decrease when said comparison signal pulse is greater than said second reference signal.
- 12. The cathode current control circuit of claim 11 wherein said counting means includes a plurality of binary counters.
- 13. A cathode current control circuit for use with a pulsed gridded device having a cathode current, comprising:
- means for providing first and second reference voltages indicative of a predetermined cathode current level, said first reference voltage being less than said second reference voltage;
- sensing means responsive to the cathode current for providing comparison voltage pulses representative of cathode current pulses;
- a first voltage comparator responsive to said comparison voltage pulses and said first reference voltage for selectively providing a coarse adjust signal when a comparison voltage pulse is less than said first reference voltage;
- second comparison means responsive to said comparison voltage pulses and said second reference voltage for providing a fine adjust signal indicative of whether said comparison voltage pulse is less than said second reference voltage;
- clocking means responsive to said comparison voltage pulses for providing clock pulses delayed relative to said comparison voltage pulses; and
- a counter circuit clocked by said delayed clock pulses and responsive to said coarse adjust signal and said fine adjust signal for providing a counter output indicative of an adjusted cathode current level, said counter circuit providing a substantially increased counter output in response of said coarse adjust signal and further providing a small incremental change in said counter output in response to the presence or absence of said fine adjust signal; and
- a digital to analog converter responsive to said counter output for providing an analog control voltage which is utilized to control the cathode current level.
- 14. A cathode current control circuit for use with a pulsed traveling wave tube (TWT) having a cathode current, comprising:
- means for providing a comparison signal indicative of the occurrence and amplitude of a TWT cathode current pulse;
- comparing means for comparing said comparison signal with at least two predetermined reference signals indicative of a predetermined cathode current level, said comparing means for providing adjustment signals indicative of the adjustment of the TWT cathode current necessary to tend to achieve said predetermined cathode current;
- clocking means responsive to said comparison signal for providing a clock pulse which occurs after termination of a selected cathode current pulse; and
- control means supplied with said clock pulse and responsive to said adjustment signals for generating a control signal indicative of an adjusted TWT cathode current level after receipt of said clock pulse.
- 15. The cathode current control circuit of claim 1 wherein said comparing means comprises:
- coarse adjustment comparison means responsive to said comparison signal and a first of said at least two predetermined reference signals for providing a coarse adjustment signal indicative of whether a large adjustment of the cathode current level is required; and
- fine adjustment comparison means responsive to said comparison signal and a second of said at least two predetermined reference signals for providing a fine adjustment signal indicative of whether a fine adjustment of the cathode current level is required.
Government Interests
The United States Government has rights to this invention pursuant to Contract No. DAAK20-81-C-0390 awarded by the Department of the Army.
US Referenced Citations (7)