초록 ▼

A method and a transmitter system is provided for modulating binary information on a frequency shift keying carrier in a very narrow band. Phase reversal keying is initially used to create a carrier. The transmitter of the present invention generates a carrier signal by modulating a reference signal

A method and a transmitter system is provided for modulating binary information on a frequency shift keying carrier in a very narrow band. Phase reversal keying is initially used to create a carrier. The transmitter of the present invention generates a carrier signal by modulating a reference signal and a control signal having two frequencies representing the binary data to be transmitted. The resulting phase reversal carrier signal is processed by high order filtering such that the output of the transmitter provides a frequency shift keyed carrier at very close frequencies. The resulting carrier signal may, at the receiver, be processed by very narrow band filtering so as to create a communication system which will use only a small part of the available spectrum.

대표청구항 ▼

[ What is claimed is:] [1.] A transmitter for transmitting an FSK output signal, said transmitter comprising:a circuit for receiving a binary data signal, for generating a reference signal, and for generating a control signal having a first frequency and a second frequency in response to the binary

[ What is claimed is:] [1.] A transmitter for transmitting an FSK output signal, said transmitter comprising:a circuit for receiving a binary data signal, for generating a reference signal, and for generating a control signal having a first frequency and a second frequency in response to the binary data signal;a modulator coupled to said circuit for phase reversal keying modulation of the reference signal with the control signal to create a carrier signal having a first carrier frequency component and a second carrier frequency component; anda high order filter with a narrow bandwidth to filter the carrier signal, whereby an FSK carrier signal with a narrow bandwidth is created.