Flip-flop and hold phase detector

Claim 2

A phase comparator comprising: a first bistable multivibrator comprising first and second cross coupled NAND gates, said multivibrator changing state in response to a first pulse signal; a second bistable multivibrator comprising third and fourth cross coupled NAND gates, said second multivibrator changing state in response to a second pulse signal; a fifth NAND gate, having input terminals coupled to the first and fourth NAND gates and an output terminal coupled to the second and third NAND gates, said fifth NAND gate changing state when positive signals appear at its two input terminals, so that the signal appearing at its output terminal causes the second and third NAND gates to change state, whereby the first and second multivibrators return to their initial state; first and second active elements each having first and second main electrodes and a control electrode; a zener diode having first and second electrodes, the first electrode thereof being coupled to the output of the first multivibrator and the second electrode thereof being coupled to the control electrode of the first active element, wherein the active element will be rendered conducting when the first multivibrator has changed state in response to a pulse signal; means for applying a first bias voltage between a point of reference potential and a first of said main electrodes of the first active element; means For connecting the second main electrode of the first active element and the first main electrode of the second active element, said means including a junction point; means for applying a second bias voltage between the point of reference potential and said first main electrode of the second active element; the second of said main electrodes of the second active element being coupled to the point of reference potential; the control electrode of the second active element being coupled to the output terminal of the second multivibrator, so that when a pulse causes the second multivibrator to change state, the second active element begins to conduct; and a capacitive energy storage means connected between said junction point and said point of reference potential, said capacitive energy storage means storing charge when only the first active element is conducting, said capacitive energy storage means losing charge when only the second active element is conducting and said capacitive energy storage means being charged to a fixed level when both the first and second active elements are conducting.

Claim 3

A phase comparator according to claim 1 wherein said capacitive energy storage means has a predetermined time constant that is substantially greater than the time interval between said first pulse and said second pulse.

Claim 4

A phase comparator according to claim 1 wherein said junction point is formed by two series connected diodes having substantially matched volt-ampere characteristics.

Claim 5

A phase comparator according to claim 1 further comprising a first and second time delay network, respectively connected in circuit with the first and second input terminals of said fifth NAND gate.

Claim 6

A phase comparator, comprising: a first bistable multivibrator comprising first and second cross coupled NAND gates, said multivibrator changing state in response to a first pulse signal; a second bistable multivibrator comprising third and fourth cross coupled NAND gates, said second multivibrator changing state in response to a second pulse signal; a fifth NAND gate, having input terminals coupled to the first and fourth NAND gates and an output terminal coupled to the second and third NAND gates, said fifth NAND gate changing state when positive signals appear at its two input terminals, so that the signal appearing at its output terminal causes the second and third NAND gates to change state, whereby the first and second multivibrators return to their initial state; first and second active elements each having first and second main electrodes and a control electrode; a zener diode having cathode and anode electrodes, the anode electrode being coupled to the output of the first multivibrator and the cathode electrode being coupled to the control electrode of the first active element, wherein the active element will be rendered conducting when the first multivibrator has changed state in response to a pulse signal; means for applying a first bias voltage between a point of reference potential and a first of said main electrodes of the first active element; first and second diodes each having cathode and anode electrodes; the junction of the cathode electrode of the first diode and the anode electrode of the second diode defining a first junction; the anode electrode of the first diode being coupled to the second of said main electrodes of the first active element, the cathode element of the first diode being coupled to the first junction, and the cathode electrode of the second diode being coupled to a first of said main electrodes of the second active element; means for applying a second bias voltage between the point of reference potential and said first main electrode of the second active element; the second of said main electrodes of the second active element being coupled to the point of reference potential, the control electrode of the second active element being coupled to the output terminaL of the second multivibrator, so that when a pulse causes the second multivibrator to change state, the second active element begins to conduct; and a first capacitor having one terminal coupled to the first junction and a second terminal coupled to a current limiting resistor, said capacitor storing charge when only the first active element is conducting, said capacitor losing charge when only the second active element is conducting and said capacitor being charged to a fixed level when both the first and second active elements are conducting, the other terminal of the current limiting resistor being coupled to the point of reference potential.

Claim 7

A phase comparator, comprising: a first bistable multivibrator comprising first and second cross coupled NAND gates, said multivibrator changing state in response to a first pulse signal; a second bistable multivibrator comprising third and fourth cross coupled NAND gates, said second multivibrator changing state in response to a second pulse signal; a fifth NAND gate, having input terminals coupled to the first and fourth NAND gates and an output terminal coupled to the second and third NAND gates, said fifth NAND gate changing state when positive signals appear at its two input terminals, so that the signal appearing at its output terminal causes the second and third NAND gates to change state, whereby the first and second multivibrators return to their initial state; first and second active elements each having first and second main electrodes and a control electrode; a zener diode having cathode and anode electrodes, the anode electrode being coupled to the output of the first multivibrator and the cathode electrode being coupled to the control electrode of the first active element, wherein the active element will be rendered conducting when the first multivibrator has changed state in response to a pulse signal; means for applying a first bias voltage between a point of reference potential and a first of said main electrodes of the first active element; first and second diodes each having cathode and anode electrodes; the junction of the cathode electrode of the first diode and the anode electrode of the second diode defining a first junction; the anode electrode of the first diode being coupled to the second of said main electrodes of the first active element, the cathode element of the first diode being coupled to the first junction, and the cathode electrode of the second diode being coupled to a first of said main electrodes of the second active element; means for applying a second bias voltage between the point of reference potential and said first main electrode of the second active element; the second of said main electrodes of the second active element being coupled to the point of reference potential, the control electrode of the second active element being coupled to the output terminaL of the second multivibrator, so that when a pulse causes the second multivibrator to change state, the second active element begins to conduct; and a first capacitor having one terminal coupled to the first junction and a second terminal coupled to a current limiting resistor, said capacitor storing charge when only the first active element is conducting, said capacitor losing charge when only the second active element is conducting and said capacitor being charged to a fixed level when both the first and second active elements are conducting, the other terminal of the current limiting resistor being coupled to the point of reference potential.