03967202 is referenced by 194 patents and cites 6 patents.

A data transmission system for obtaining information from a plurality of data sources includes an interrogate source for transmitting RF interrogate signals to the locations of the data sources and a transponder associated with each data source for receiving the interrogate signals and for generating RF reply signals representing the information. The transponder includes a transmitter having a voltage controlled oscillator responsive to data signals at first and second levels to generate sinusoidal output signals at first and second frequencies, respectively, a wave shaping circuit which converts the output signals to sawtooth wave signals at the corresponding frequencies and an FM oscillator for providing a carrier signal which is modulated by the sawtooth signals to produce a broad spectrum of sideband signals of approximately equal amplitude.

Title
Data transmission system including an RF transponder for generating a broad spectrum of intelligence bearing sidebands
Application Number
5/491829
Publication Number
3967202
Application Date
July 25, 1974
Publication Date
June 29, 1976
Inventor
James E Batz
Northbrook
IL, US
Agent
Johnson Dienner Emrich & Wagner
Assignee
Northern Illinois Gas Company
IL, US
IPC
G01S 9/56
H04B 1/59
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