Abstract: A frequency synthesizer is provided in which the output is a truly continuous sweep of frequency, not a staircase of spot frequencies. A programmable frequency divider PD is connected to the output of a voltage-controlled oscillator (VCO) to divide the VCO output by a variable integer N. At each VCO output cycle, the integer N is incremented (or decremented). The output of a phase comparator PC, which compares the divider output with a fixed reference frequency, is connected via an integrator (10) to the VCO frequency control input (2). A constant phase error produces a ramp rise of VCO frequency.

Abstract: A receiver for frequency hopped signal on which an information signal is modulated on one of a plurality of equally frequency spaced carrier signals. A mixer receives the frequency hopped signals on one input, and on a second input, a local oscillator signal have a comb spectrum. The local oscillator signal is generated by a short pseudo-random bit sequence generator providing the continuous comb spectrum with a frequency spacing equal to the spacing of the carrier frequency signals. A plurality of auxiliary signals are generated having a frequency spacing equal to the carrier frequency signal spacings. The auxiliary signals will have the same frequency and spacing from each other for all carrier frequency signals. The modulator means can be used to separate one of the frequency constant auxiliary signals which includes modulation produced from any one of the plurality of carrier signals.

Abstract: In a phase lock loop frequency synthesizer, a successive addition rate multiplier provides a correction signal for eliminating ripple in a frequency control signal applied to a variable frequency oscillator which produces the output frequency of the synthesizer. Ripple elimination is improved by means of a feedback loop by which any residual ripple is detected and the correction signal is automatically adjusted.