Patent ID: 7515931
Filing Date: 2009-04-07
Classification: H03L,H04B

Abstract:
1. A transmitter comprising: a phase locked loop (PLL) frequency synthesizer having a frequency synthesizer output; and at least one RF upconverter, each upconverter having a local oscillator input coupled to the frequency synthesizer output, the PLL frequency synthesizer comprising: a voltage controlled oscillator (VCO) to provide a VCO frequency signal; a switchable non-integer frequency multiplier circuit having a control input, the non-integer frequency multiplier accepting the VCO frequency signal and producing a frequency-multiplied signal at a non-integer multiple of the VCO output frequency or at the VCO output frequency under control of the control input; a programmable divider accepting the frequency-multiplied signal and dividing the frequency of the shifted-frequency signal by a settable amount; a phase detector to compare the phase of the output of the programmable divider to that of a reference oscillator and produce a phase difference signal; and a loop filter to filter a function of the phase difference to produce a control input to the VCO, the transmitter being configured for operation at a plurality of RF frequency bands, the RF bands disparate and each having a bandwidth, the transmitter having a intermediate frequency that is a sizable fraction of the bandwidth of one or more of the RF bands, wherein the non-integer multiple is selected such that the frequency synthesizer can supply the local oscillator signal for the plurality of RF bands, such that the tuning range of the VCO is a relatively low fraction of the VCO frequency, and such that spurious mixer products do not fall in the frequency bands of operation.