Patent ID: 7376396

Claim:
Ratiometric transmit path circuitry for a communication system operable in at least two frequency bands comprising: mixing circuitry configured to convert I and Q baseband input signals to a combined output signal at an intermediate frequency (IF); transmit circuitry coupled to receive the combined IF signal from the mixing circuitry and to output a transmit signal at a desired output frequency within at least two frequency bands, the transmit circuitry comprising offset phase lock loop (PLL) circuitry comprising: a phase detector coupled to receive the combined IF signal and to receive a feedback input signal; a transmit voltage controlled oscillator (VCO) coupled to receive the output of the phase detector, the transmit VCO having an output frequency above the desired output frequency; transmit divider circuitry coupled to receive the output of the transmit VCO and to output the transmit signal at the desired output frequency, the divider value for the transmit divider circuitry being selectable between two divider values to provide the transmit signal at the desired output frequency such that a first divider value is used for a first frequency band and a second divider value is used for a second frequency band; and transmit mixer circuitry coupled to receive the transmit signal and a mixing signal as an inputs, the output of the transmit mixer circuitry being coupled to provide the feedback input signal to the phase detector; oscillator circuitry configured to output a local oscillator (LO) signal; first divider circuitry coupled to receive the LO signal and to output an IF mixing signal to the mixing circuitry, the divider value for the first divider circuitry being a single divider value such that the single divider value is used for the first frequency band and the second frequency band; and second divider circuitry coupled to receive the LO signal and to output the mixing signal to the transmit circuitry, the divider value for the second divider circuitry being selectable between to divider values such that a first divider value is used for the first frequency band and a second divider value being used for the second frequency band.