Abstract: Circuits and methods for identifying or verifying frequencies are disclosed herein. A frequency verification circuit comprises: an input port for receiving an input signal; a phase frequency difference detector for determining a difference in phase and frequency between the input signal and a feedback signal and for providing a control signal based on the detected difference; a voltage controlled crystal oscillator for producing an output signal based on the control signal; and a feedback loop including a feedback divider for frequency dividing the output signal by a factor R to produce the feedback signal, the feedback divider being programmable to a plurality of values of the factor R to correspond to a plurality of different test frequencies.

Abstract: A digitally compensated phase locked oscillator (DCPLO) is disclosed herein. The DCPLO comprises: a DCPLO input for receiving a reference signal at a known frequency; a DCPLO output for outputting a signal at a desired frequency; a phased locked loop (PLL), the phased locked loop comprising: a phase frequency detector, an oscillator, and a PLL output coupled to the output; a first direct digital synthesizer (DDS), the first DDS having an output coupled to the PLL to supply a DDS signal to the PLL for adjusting the frequency within the PLL so as to maintain phase lock over the operating temperature; a temperature sensor; and a processor coupled to the first DDS, the phase frequency detector, and the temperature sensor, the processor configured to set the frequency of the first DDS according to a temperature sensed by the temperature sensor.

Abstract: An offset phase locked loop synthesizer comprising: an input; an output; a voltage controlled oscillator (VCO), the VCO output coupled to the synthesizer output; a phase frequency detector having a reference input, a feed-back input, and an output; a mixer having a first mixer input coupled to the synthesizer input and a second mixer input coupled to the VCO output; a first divider for frequency dividing a signal by a first value and having an input coupled to the mixer output and an output coupled to the second input of the phase frequency detector; a second divider for frequency dividing a signal by a second value and having an input coupled to the synthesizer input and an output coupled to the reference input of the phase frequency detector; and a low pass filter coupled between the output of the phase frequency detector and the VCO input.

Abstract: An apparatus and method for providing an output signal. The apparatus comprises an input for receiving a reference signal, an oscillator for providing an output signal, and an offset signal generator for frequency multiplying the reference signal to generate an offset signal that has a plurality of frequency products in a plurality of frequency bands. The apparatus further includes a mixer for mixing the offset signal with the output signal to produce a combined signal, an offset frequency selector for controllably selecting a frequency band of the offset signal, and a difference detector for detecting a difference between the reference signal and the combined signal and for providing a control signal to the oscillator based on the detected difference.

Abstract: Circuits and methods for identifying or verifying frequencies are disclosed herein. A frequency verification circuit comprises: an input port for receiving an input signal; a phase frequency difference detector for determining a difference in phase and frequency between the input signal and a feedback signal and for providing a control signal based on the detected difference; a voltage controlled crystal oscillator for producing an output signal based on the control signal; and a feedback loop including a feedback divider for frequency dividing the output signal by a factor R to produce the feedback signal, the feedback divider being programmable to a plurality of values of the factor R to correspond to a plurality of different test frequencies.