Self-oscillating limiter

Claim 2

Apparatus for providing an amplified and limited output in response to an input signal having an amplitude above a threshold level and for providing an oscillatory output in response to an input signal having an amplitude below said threshold level comprising: input means for receiving an input signal, means for amplifying and limiting a signal, means connecting said input means to said amplifying and limiting means, means for biasing said amplifying and limiting means off in the absence of an input signal above a threshold level, oscillator means, means response to the conductive state of said amplifying and limiting means for turning on said oscillator means when said amplifying and limiting meanS is turned off, means for combining the outputs of said oscillator means and said amplifying and limiting means.

Claim 3

Apparatus according to claim 1 wherein said oscillator means comprises semiconductor means in a feedback arrangement with an RLC tank circuit.

Claim 4

A self-oscillating limiter circuit for the processing of video signals comprising: a pair of input terminals connectable to receive an input signal, first and second transistors, means for connecting said input terminals to the bases of said first and second transistors, respectively, means for biasing said transistors off in the absence of an input signal above a threshold level, third and fourth transistors, an RLC tank circuit, means for coupling the bases of said third and fourth transistors to said tank circuit, first and second current sources, means for connecting the emitters of said first and third transistors together to said first current source, whereby the conduction state of said third transistor is controlled by said first transistor, means for connecting the emitters of said second and fourth transistors together to said second current source, whereby the conduction state of said fourth transistor is controlled by said second transistor, means for coupling the collectors of said first and second transistors to said RLC tank circuit, means for coupling the bases of said third and fourth transistors to said RLC tank circuit, first and second output terminals, means for connecting the collector of said third transistor to said first output terminal, and means for connecting the collector of said fourth transistor to said second output terminal.

Claim 5

A self-oscillating limiter circuit for the processing of video signals comprising: a pair of input terminals connectable to receive an input signal, first and second transistors, means for connecting said input terminals to the bases of said first and second transistors, respectively, means for biasing said transistors off in the absence of an input signal above a threshold level, third and fourth transistors, an RLC tank circuit, means for coupling the bases of said third and fourth transistors to said tank circuit, first and second current sources, means for connecting the emitters of said first and third transistors together to said first current source, whereby the conduction state of said third transistor is controlled by said first transistor, means for connecting the emitters of said second and fourth transistors together to said second current source, whereby the conduction state of said fourth transistor is controlled by said second transistor, means for coupling the collectors of said first and second transistors to said RLC tank circuit, means for coupling the bases of said third and fourth transistors to said RLC tank circuit, first and second output terminals, means for connecting the collector of said third transistor to said first output terminal, and means for connecting the collector of said fourth transistor to said second output terminal.

Claim 6

Apparatus for providing an amplified output signal in response to an input signal having an amplitude above a threshold level and for providing an oscillatory output in response to an input signal having an amplitude below said threshold level comprising difference amplifier means having first and second inputs and first and second outputs associated with each input, respectively, constant current source means connected to said difference amplifier means, means for applying said input signal to said first input, resonant tank circuit means, means for connecting said resonant tank circuit means in an oscillatory feedback path between said first output and said second input, and means connected to said second output for providing said output signal.

Claim 7

Apparatus for providing an amplified output signal in response to an input signal having an amplitude above a threshold level and for providing an oscillatory output in response to an input signal having an amplitude below said threshold level comprising difference amplifier means having first and second inputs and first and second outputs associated with each input, respectively, constant current source means connected to said difference amplifier means, means for applying said input signal to said first input, resonant tank circuit means, means for connecting said resonant tank circuit means in an oscillatory feedback path between said first output and said second input, and means connected to said second output for providing said output signal.

Claim 8

The combination of claim 4 further comprising biasing means connected to said first input for establishing a predetermined threshold level.

Claim 9

The combination of claim 5 wherein said difference amplifier means comprises a pair of transistors having their emitters connected together to said constant current source means and wherein said first and second inputs are the respective bases of said transistors and said first and second outputs are the collectors of said transistors.