Method and apparatus for demodulating a phase reversal modulated alternating current wave

Claim 2

A demodulator for deriving an output signal from an alternating current wave modulated by phase reversals including the combination of means for limiting the wave to a predetermined amplitude, a resonator coupled to said amplitude limiting means, rectifying means coupled to said resonator and a threshold circuit coupled to said rectifying means for deriving an output signal identifying the phase reversals of said alternating current wave.

Claim 3

A demodulator for deriving an output signal from an alternating current wave having a given frequency which is modulated by 0* - 180* phase reversals which bear binary data in accordance with which the lack of a phase reversal indicates one binary value and a phase reversal indicates another binary value including the combination of an amplitude limiter for receiving the wave and for limiting the amplitude of the wave to a predetermined amplitude, a resonator having a resonant frequency corresponding to said given frequency coupled to said amplitude limiter, said resonator being adapted to provide an output signal which varies in amplitude in accordance with the phase reversals of said alternating current wave, a rectifier coupled to said resonator, a low pass filter coupled to said rectifying means for providing an output signal having a wave shape corresponding to the amplitude varying envelope of the wave appearing at the output of the resonator and a threshold circuit coupled to said low pass filter for providing a binary output signal which changes from one value to another value in accordance with phase reversals of the alternating current wave.

Claim 4

A demodulator for deriving an output signal from an alternating current wave having a given frequency which is modulated by 0* - 180* phase reversals which bear binary data in accordance with which the lack of a phase reversal indicates one binary value and a phase reversal indicates another binary value including the combination of an amplitude limiter for receiving the wave and for limiting the amplitude of the wave to a predetermined amplitude, a resonator having a resonant frequency corresponding to said given frequency coupled to said amplitude limiter, said resonator being adapted to provide an output signal which varies in amplitude in accordance with the phase reversals of said alternating current wave, a rectifier coupled to said resonator, a low pass filter coupled to said rectifying means for providing an output signal having a wave shape corresponding to the amplitude varying envelope of the wave appearing at the output of the resonator and a threshold circuit coupled to said low pass filter for providing a binary output signal which changes from one value to another value in accordance with phase reversals of the alternating current wave.

Claim 5

A demodulator in accordance with claim 2 in which the resonator comprises a series resonant circuit having a resonant frequency equal to the said given frequency of said alternating current wave and having a Q selected to enable the output signal from the resonator to decrease in amplitude in response to a phase reversal to a minimum value at which the phase of the output signal from the resonator reverses and commences to increase within a preselected period determined by the rate of transmission of binary data.

Claim 6

A demodulator for deriving an output signal from an alternating current wave bearing binary coded digital information transmitted at a given bit rate and in which one binary value is represented by a lack of reversal of phase of the wave and another binary value is represented by a reversal phase of the wave including the combination of means for receiving the alternating current wave and for limiting the wave to a predetermined amplitude, a resonator coupled to said amplitude limiting means having a preselected Q which enables the resonator upon a reversal of phase of the alternating current wave to provide an output signal which is amplitude modulated within the time interval between the appearance of successive bits of information within said given bit rate, rectifying means coupled to the resonator, a low pass filter coupled to said rectifying means for providing an output signal corresponding to the envelope of the signal appearing at the output of the resonator, and a threshold circuit coupled to said low pass filter for deriving an output signal identifying the phase reversals of said alternating current wave.

Claim 7

A demodulator for deriving an output signal from an alternating current wave bearing binary coded digital information transmitted at a given bit rate and in which one binary value is represented by a lack of reversal of phase of the wave and another binary value is represented by a reversal phase of the wave including the combination of means for receiving the alternating current wave and for limiting the wave to a predetermined amplitude, a resonator coupled to said amplitude limiting means having a preselected Q which enables the resonator upon a reversal of phase of the alternating current wave to provide an output signal which is amplitude modulated within the time interval between the appearance of successive bits of information within said given bit rate, rectifying means coupled to the resonator, a low pass filter coupled to said rectifying means for providing an output signal corresponding to the envelope of the signal appearing at the output of the resonator, and a threshold circuit coupled to said low pass filter for deriving an output signal identifying the phase reversals of said alternating current wave.

Claim 8

In a system in which binary data is transmitted by reversing the phase of an alternating current wave to represent one binary value while transmitting the alternating current wave without phase reversal to represent another binary value and in which binary data is transmitted at a given bit rate the combination of an amplitude limiter to which the alternating current wave is applied and which provides at its output a wave having a substantially predetermined amplitude irrespective of the ampLitude of the wave applied to the limiter over a wide range of values, a resonator coupled to the limiter for receiving the amplitude limited wave, said resonator having a resonant frequency corresponding to the alternating current wave and having the capability of responding to a reversal in phase of the alternating current wave with a reduction in the amplitude of the wave appearing at its output corresponding to each phase reversal of the alternating current wave, and a threshold circuit coupled to said resonator for deriving an output signal representing phase reversals of the alternating current wave.

Claim 9

In a system in which binary data is transmitted by reversing the phase of an alternating current wave to represent one binary value while transmitting the alternating current wave without phase reversal to represent another binary value and in which binary data is transmitted at a given bit rate the combination of an amplitude limiter to which the alternating current wave is applied and which provides at its output a wave having a substantially predetermined amplitude irrespective of the ampLitude of the wave applied to the limiter over a wide range of values, a resonator coupled to the limiter for receiving the amplitude limited wave, said resonator having a resonant frequency corresponding to the alternating current wave and having the capability of responding to a reversal in phase of the alternating current wave with a reduction in the amplitude of the wave appearing at its output corresponding to each phase reversal of the alternating current wave, and a threshold circuit coupled to said resonator for deriving an output signal representing phase reversals of the alternating current wave.

Claim 10

Apparatus in accordance with claim 5 in which a rectifier is coupled to the output of the resonator and a low pass filter is connected between the output of the rectifier and the threshold circuit.

Claim 11

In a binary data transmission system in which an alternating current wave bears binary information in the form of phase reversals representing one binary value and a lack of phase reversals representing another binary value, a demodulator for deriving an output signal from the alternating current wave including the combination of means for applying an amplitude limited wave corresponding to said alternating current wave to the demodulator, a resonator coupled to the amplitude limiting means having a frequency corresponding to the alternating current wave, and means deriving an output signal from the resonator identifying each phase reversal of the alternating current wave.

Claim 12

In a binary data transmission system in which an alternating current wave bears binary information in the form of phase reversals representing one binary value and a lack of phase reversals representing another binary value, a demodulator for deriving an output signal from the alternating current wave including the combination of means for applying an amplitude limited wave corresponding to said alternating current wave to the demodulator, a resonator coupled to the amplitude limiting means having a frequency corresponding to the alternating current wave, and means deriving an output signal from the resonator identifying each phase reversal of the alternating current wave.