摘要:
A method of calibrating a radio receiver (100) which has a desired IF center frequency (fo) includes generating and applying to the receiver's demodulator (126) a plurality of reference signals. The demodulated reference signals are used to generate, for the demodulator, a transfer function that is predictive of amplitude versus frequency characteristics of signals to be demodulated by the demodulator (126). The transfer function (202) is used to determine a frequency offset between a received signal's intermediate frequency and the desired frequency fo. The determined frequency offset is used to adjust the IF frequency of the received signal towards the desired frequency fo. The adjustment process preferably continues until the frequency offset is below a desired threshold. A receiver using the disclosed method is also described.
摘要:
A transceiver synthesizer includes components that enable it to be tuned non-invasively by software. The transceiver synthesizer includes a non-volatile memory (30) that can be non-invasively programmed with a digital value for each of a number of tuning variables. The digital values are converted by digital to analog converters (37, 38, 39) into tuning voltages. The tuning voltages are applied to voltage variable devices (60, 80, 95) that respond to changes in the applied tuning voltage to vary an operating characteristic thereof. The operating characteristics of the voltage variable devices (60, 80, 95) are non-invasively adjustable to tune the transceiver synthesizer for high and low port modulation deviation, reference oscillator make tolerance, automatic frequency control, reference oscillator temperature compensation etc.