Signal processing circuit

Claim 2

A signal processing circuit including in combination: first differential amplifier means comprising first and second amplifier devices each having first, second and control electrodes, with the first electrodes thereof coupled with a first common terminal; means for applying an input signal to the control electrode of at least one of said first and second amplifier devices; at least one additional differential amplifier means comprising third and fourth amplifier devices each having first, second and control electrodes, with the first electrodes of said third and fourth amplifier devices being coupled in common with the second electrode of said first amplifier device; reactance means coupled in circuit between the second electrode of said second amplifier device and the second electrode of one of said third and fourth amplifier devices; control means coupled with the control electrode of at least one of said third and fourth amplifier devices for applying a control potential thereto to vary the relative gains of said third and fourth amplifier devices; and output means coupled with the second electrode of at least one of said second, third and fourth amplifier devices for providing an output signal having a predetermined phase relationship with respect to the phase of said input signal.

Claim 3

The combination according to claim 1 further including shunt gate means connected across the first and second electrodes of said first and second amplifier devices and rendered conductive and nonconductive in response to a gating signal; and means for applying gating signals to said shunt gate means.

Claim 4

The combination according to claim 1 wherein said signal processing circuit is fabricated as a monolithic integrated circuit.

Claim 5

The combination according to claim 1 including first and second voltage supply terminals for connection across a direct current supply voltage and means for coupling the second electrodes of said second, third and fourth amplifier devices with said first voltage supply terminal and means for coupling the first common terminal with said second voltage supply terminal.

Claim 6

The combination according to claim 4 wherein said reactance means is capacitive means and further including first and second load resistors, the resistance of said first load resistor being substantially twice the resistance of said second load resistor, said first load resistor coupled between the second electrode of said second amplifier device and said first voltage supply terminal, said second load resistor coupled between the second electrode of said fourth amplifier device and said first supply terminal, wherein the second electrode of said third amplifier device is coupled directly with said first voltage supply terminal; and said capacitive means is coupled between the second electrodes of said second and fourth amplifier devices.

Claim 7

The combination according to claim 5 wherein said means for coupling the first common terminal with said second voltage supply terminal comprises cuRrent source means.

Claim 8

The combination according to claim 1 wherein said control means comprises a differential direct current voltage source coupled across the control electrode of said third and fourth amplifier devices.

Claim 9

The combination according to claim 7 wherein said differential direct current voltage source comprises a phase comparator circuit having first and second input circuits for receiving first and second alternating current signals to be compared and having first and second outputs coupled with the control electrodes of said third and fourth amplifier devices, respectively, with differential direct current voltage levels being developed on said first and second outputs in accordance with the phase relationship of input signals applied to the first and second inputs thereof.

Claim 10

The combination according to claim 8 wherein the signal applied to the first imput of said phase comparator comprises said output signal provided by said output means.

Claim 11

The combination according to claim 1 further including a third differential amplifier circuit means comprising fifth and sixth amplifier devices, each having first, second and control electrodes, with the first electrodes thereof coupled in common with the second electrode of said second amplifier device, the control electrodes of said fourth and fifth amplifier devices coupled together at a second common terminal and the control electrodes of said third and sixth amplifier devices coupled together at a third common terminal; means interconnecting the second electrodes of said third and fifth amplifier devices; and means interconnecting the second electrodes of said fourth and sixth amplifier devices.

Claim 12

The combination according to claim 10 wherein said control means comprises a differential direct current voltage source connected across the second and third common terminals for differentially varying the gain of said third and fourth amplifier devices and for differentially varying the gain of said fifth and sixth amplifier devices.

Claim 13

The combination according to claim 11 wherein said differential direct current voltage course comprises a phase comparator circuit having first and second input circuits for receiving first and second alternating current input signals to be compared and having first and second outputs coupled, respectively, to the second and third common terminals, a differential direct current voltage being developed across the first and second outputs in accordance with the relationship of input signals applied to the first and second inputs thereof.

Claim 14

The combination according to claim 10 wherein said reactance means is capacitive means and further including first and second voltage supply terminals, current source means coupling the first common terminal with said second voltage supply terminal, first and second resistance means coupled together at a first junction and connected in series between the second electrode of said third amplifier device and said voltage supply terminal; third and fourth resistance means coupled together at a second junction and connected in series between the second electrode of said fourth amplifier device and said first voltage supply terminal, said second electrodes of said fifth and sixth amplifier devices connected respectively to said first and second junctions; and wherein said capacitance means is connected between the second electrodes of said third and fourth amplifier devices.

Claim 15

The combination according to claim 13 further including means for connecting frequency determining means between the second electrode of one of said third, fourth, fifth and sixth amplifier devices and the control electrode of one of said first and second amplifier devices.

Claim 16

The combination according to claim 14 wherein said means for connecting frequency determining means is coupled between the second electrode of said fourth amplifier device and the control electrode of said second amplifier device.

Claim 17

The combination according to claIm 15 wherein said control means comprises a differential direct current voltage source connected across the second and third common terminals.

Claim 18

The combination according to claim 16 further including means for providing a reference signal and wherein said differential direct current voltage source comprises a phase comparator circuit having first and second input circuits, with the first input circuit coupled with said output means to receive said output signal and the second input circuit coupled with said means for providing a reference signal, said phase comparator having first and second outputs coupled respectively with the second and third common terminals.

Claim 19

The combination according to claim 16 further including shunt gate means for enabling and disabling said phase comparator circuit in response to gating signals, and means for applying gating signals to said shunt gate means.

Claim 20

A signal processing circuit including in combination: first differential amplifier means comprising first and second amplifier devices each having first, second and control electrodes, with the first electrodes thereof coupled with a first common terminal; means for applying a first alternating current input signal to the control electrode of at least one of said first and second amplifier devices; means for applying a second alternating current input signal to said first common terminal; at least one additional differential amplifier means comprising third and fourth amplifier devices each having first, second and control electrodes with the first electrodes of said third and fourth amplifier devices being coupled at a common current node, the second electrode of said first amplifier device coupled with the control electrode of said third amplifier device; a fifth amplifier device having first, second and control electrodes, with the control electrode of said fifth amplifier device coupled with the second electrode of said fourth amplifier device and the first electrode of said fifth amplifier device coupled with the control electrode of said fourth amplifier device; coupling means coupling the second electrodes of at least said second, third, fourth and fifth amplifier devices with a source of operating potential; output means coupled with the second electrode of said third amplifier device for providing an output signal from said processing circuit; and means coupled with the control electrode of said third amplifier device for providing a variable control potential thereto.

Claim 21

A signal processing circuit including in combination: first differential amplifier means comprising first and second amplifier devices each having first, second and control electrodes, with the first electrodes thereof coupled with a first common terminal; means for applying a first alternating current input signal to the control electrode of at least one of said first and second amplifier devices; means for applying a second alternating current input signal to said first common terminal; at least one additional differential amplifier means comprising third and fourth amplifier devices each having first, second and control electrodes with the first electrodes of said third and fourth amplifier devices being coupled at a common current node, the second electrode of said first amplifier device coupled with the control electrode of said third amplifier device; a fifth amplifier device having first, second and control electrodes, with the control electrode of said fifth amplifier device coupled with the second electrode of said fourth amplifier device and the first electrode of said fifth amplifier device coupled with the control electrode of said fourth amplifier device; coupling means coupling the second electrodes of at least said second, third, fourth and fifth amplifier devices with a source of operating potential; output means coupled with the second electrode of said third amplifier device for providing an output signal from said processing circuit; and means coupled with the control electrode of said third amplifier device for providing a variable control potential thereto.

Claim 22

The combination according to claim 19 further including a gating amplifier device having first, second and control electrodes, with the first and second electrodes thereof coupled between the first common terminal and said coupling means, said gating amplifier device being normally conductive to render said signal processing circuit non-responsive to said first and second alternating current input signals and being rendered nonconductive in response to a gate pulse applied to the control electrode thereof to render said signal processing circuit responsive to said first and second input signals; and means for applying a gate pulse to the control electrode of said gating amplifier device.