Inventors:
Paul G. Wulfsberg - Overland Park KS
Dennis L. Fredrickson - Leawood KS
Gregory L. Triplett - Olathe KS
Ralph J. Crumrine - Olathe KS
Cole E. Cunningham - Dallas TX
International Classification:
H03L 718, H03C 309
Abstract:
A frequency synthesizer employing direct FM, as opposed to phase modulation, so subaudible tones may be transmitted, in the form of a 10 KHz increment, direct synthesizer with a skewed frequency standard deriving four intermediate 2. 5 KHz tuning steps. Fast settling time of frequency change accommodates semi duplex operation, and a shaping network provides the amount of skewing changes required between band ends for substantially perfect tracking. A low division ratio programmed divider in the system maximizes transmitter signal to noise ratio, and a low pass filter in the synthesizer phase locked loop allows voice band moduation.