Patent
Phase locked loop for generating two disparate, variable frequency signals
TLDR
In this paper, a phase comparator is used to compare the reference signal with a feedback signal, which is then fed to a variable frequency divider circuit under control of a Σ/Δ converter to generate a lower frequency signal.Abstract:
A method and apparatus for generating two disparate frequency reference signals using a single phase locked loop. The circuit includes a local oscillator for generating a reference signal and a phase comparator for comparing the reference signal with a feedback signal. The output of the phase comparator is converted to a first one of the desired output frequencies by a voltage controlled oscillator. That signal is also fed to a variable frequency divider circuit under control of a Σ/Δ converter which generates a lower frequency signal without creating a secondary frequency tone. The lower frequency signal is the second of the output frequencies. This signal also is fed back to the second input of the phase comparator through a fixed frequency divider.read more
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TL;DR: In this article, a local oscillator for radio frequency communication systems is described, which includes a regenerative modulator comprising a pair of frequency dividers and a single side band mixer.
References
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Patent
Multiple-modulator fractional-n divider
TL;DR: In this paper, a fractional-N type frequency synthesizer includes a frequency divider having a selectable integer divide number which is periodically temporarily altered to provide an average rational divide number for the frequency dividers.
Patent
Frequency synthesizers having dividing ratio controlled by sigma-delta modulator
TL;DR: In this paper, a variable modulus divider is used to divide the output signal to provide the phase control signal, whose frequency varies in dependence upon a ratio control signal derived by a second or higher order sigma-delta modulator in response to a frequency control signal.
Patent
Frequency synthesizer with fractional division ratio and jitter compensation
TL;DR: In this article, a frequency synthesizer with good resolution is obtained by a unity increase of the dividing ratio for a controlled proportion of the reference frequency cycles thus giving a fractional dividing ratio.
Patent
Heterodyne radio receiver with plural variable frequency local oscillator signals
TL;DR: In this article, a satellite navigation receiver uses common dual-conversion superheterodyne and frequency synthesizer circuitry for receiving signals from both the GPS and the GLONASS satellite navigation systems.
Patent
Linear low noise phase-frequency detector
TL;DR: In this paper, a phase-frequency detector (110) includes an output stage (300) and a control stage (200), which are coupled to a charge pump output node (111).