1
Michael H Perrott, Charles G Sodini, Anantha P Chandrakasan: Digital compensation for wideband modulation of a phase locked loop frequency synthesizer. Massachusetts Institute of Technology, Theresa A Lober, December 28, 1999: US06008703 (264 worldwide citation)

A digital compensation filtering technique is provided that enables indirect phase locked loop modulation with a digital modulation data stream having a bandwidth that exceeds, perhaps by an order of magnitude, the bandwidth characteristic of the phase locked loop. A modulation data receiver is prov ...


2
Timo Gossmann, Edmund Götz: Digital PLL (phase-locked loop) frequency synthesizer. Infineon Technologies, Herbert L Lerner, Laurence A Greenberg, Werner H Stemer, March 19, 2002: US06359950 (95 worldwide citation)

The circuit compensates for phase error in the case of fractional-N-based PLL frequency synthesizers. All required actuating and reference signals are derived from the VCO frequency of the voltage-controlled oscillator by using an auxiliary phase-locked loop. The circuit is specifically applicable f ...


3
Yoshiaki Tarusawa, Shigeki Saito, Yasushi Yamao, Toshio Nojima: Frequency synthesizer having compensation for nonlinearities. Nippon Telegraph and Telephone Corporation, Cushman Darby & Cushman, December 25, 1990: US04980652 (82 worldwide citation)

In a phase locked loop frequency synthesizer, the frequency of a VCO is switched by changing the division ratio of a variable ratio frequency divider in the feedback path of the loop. At the time of switching, a prepositioning voltage is applied to the VCO to realize fast frequency switching. To cor ...


4
Robert K Kimura, Benedict A Itri: PLL Fast frequency synthesizer with memories for coarse tuning and loop gain correction. TRW, Robert M Wallace, Noel F Heal, February 4, 1986: US04568888 (74 worldwide citation)

A phase-locked loop frequency synthesizer apparatus for providing an output signal whose frequency jumps from one value to another, at regular intervals of time. Coarse tuning circuitry couples a prescribed signal to the apparatus' voltage-controlled oscillator (VCO), to drive the VCO immediately to ...


5
Fumitaka Asami: Lock detecting circuit for phase-locked loop frequency synthesizer. Fujitsu, Staas & Halsey, March 13, 1984: US04437072 (73 worldwide citation)

A phase-locked loop circuit comprising a reference oscillator (1), a reference frequency divider (2) for dividing the output signal of the reference oscillator, a programmable frequency divider (3), a phase comparator (4) for monitoring the difference in phase between the output signal of the two fr ...


6
Donald G Meyer: Controlled frequency signal source apparatus including a feedback path for the reduction of phase noise. John Fluke Mfg Co, Christensen O Connor Johnson & Kindness, June 22, 1982: US04336505 (60 worldwide citation)

A low phase noise signal source is disclosed which incorporates a voltage controlled oscillator (VCO) and a feedback network that, in effect, demodulates the VCO output signal and supplies negative feedback representative of the VCO signal noise to the VCO frequency control terminal. The feedback ne ...


7
Keith Gallardo: Method and apparatus for reducing PLL lock time. Qualcomm Incorporated, Philip Wadsworth, Charles Brown, Donald Korwich, May 4, 2004: US06731146 (58 worldwide citation)

The lock time is reduced in a phase locked loop frequency synthesizer that has both active modes and standby modes. In the active mode the frequency synthesizer operates to maintain a stable frequency output. The standby or sleep mode is used to reduce power consumption when the frequency synthesize ...


8
William J Riley Jr: Automatic pretuning of a voltage controlled oscillator in a frequency synthesizer using successive approximation. Harris Corporation, L Lawton Rogers III, June 9, 1981: US04272729 (54 worldwide citation)

The automatic pretuning of a voltage controlled oscillator in a phase locked loop frequency synthesizer utilizes a successive approximation technique to rapidly bring the coarse tuning voltage of the oscillator to the desired pretuning value. A digital number stored in a digital register is converte ...


9
Mark W McDermott, Antone L Fourcroy: Integrated circuit with clock generator. Motorola, Jonathan P Meyer, June 5, 1990: US04931748 (52 worldwide citation)

A microprocessor or other integrated circuit including a clock generator circuit which is dependent on an externally-provided reference signal includes the capability of detecting the loss of this externally-provided reference signal and producing an alternate clock signal despite the loss of the re ...


10
Hiromasa Yamanaka: Double superheterodyne multichannel receiver with a phase-locked loop frequency synthesizer. Shinto Denki, Woodcock Washburn Kurtz & Mackiewicz, May 31, 1977: US04027242 (46 worldwide citation)

A double superheterodyne receiver having a single local oscillator which supplies a signal of a predetermined frequency to a second frequency converter or mixer, where a second intermediate frequency signal is produced for final detection. The local oscillator signal is also supplied via a frequency ...