FM limiter with input level sensing and TTL level output

Claim 1

An analog limiter with input level sensing and TTL level output, comprising: Schmitt trigger means responsive to the amplitude of an analog signal applied thereto for providing a first square wave; comparator means responsive to the zero crossings of an analog signal applied thereto for providing a second square wave; means responsive to said first and second square waves for providing a data signal and a timing signal; and means responsive to both said data and timing signals for providing an output square wave having the zero crossings of said analog signal.

Claim 3

The method of deriving a digital output signal in response to an analog input signal where the output signal maintains the zero crossings of the analog input comprising the steps of: applying the analog input signal to a means responsive to the amplitude of the analog input signal; applying the analog input signal to a means responsive to the zero crossings of the analog input signal; generating a first output square wave defining a data signal in response to the amplitude of the analog input signal; generating a second output square wave in response to the zero crossings of the analog input signal; applying said first and second output square waves to a means responsive to both said first and second output square waves; generating a clock signal in response to the anticoincidence of both said first and second output square waves; applying both said data and clock signals to a means responsive to said data signal and said clock signal; and generating the digital output signal in response to said data signal and said clock signal.

Claim 4

The method of deriving a digital output signal in response to an analog input signal where the output signal maintains the zero crossings of the analog input comprising the steps of: applying the analog input signal to a means responsive to the amplitude of the analog input signal; applying the analog input signal to a means responsive to the zero crossings of the analog input signal; generating a first output square wave defining a data signal in response to the amplitude of the analog input signal; generating a second output square wave in response to the zero crossings of the analog input signal; applying said first and second output square waves to a means responsive to both said first and second output square waves; generating a clock signal in response to the anticoincidence of both said first and second output square waves; applying both said data and clock signals to a means responsive to said data signal and said clock signal; and generating the digital output signal in response to said data signal and said clock signal.