摘要:
The present invention includes an apparatus and a method for transceiver self-diagnostic testing in a communication system. A feedback unit (228, 326) is utilized that allows performance of a loopback test independent of a transmit frequency to receive frequency difference without undue proliferation of circuitry.
摘要:
A phase locked loop frequency synthesizer with DC data modulation capability is described. This synthesizer includes an arrangement for detecting one of a plurality of FSK data levels (61), generating a corresponding predetermined compensation signal (71) and utilizing the compensation signal to substantially continuously compensate the frequency synthesizer for normal response to the detected data modulation level.
摘要:
A method and apparatus for generating an output signal (616) having a pre-determined frequency shift relative to the frequency of a reference signal from a reference frequency generator (202) comprise a digital phase-locked loop (206) coupled to the reference signal for generating the output signal (616). The method and apparatus further comprise adding pulses to the reference signal in a pulse addition circuit (304), the pulses recurring at a first cyclical rate determined by a microprocessor (702). The method and apparatus further comprise concurrently subtracting pulses from the reference signal in a pulse subtraction circuit (302) at a second cyclical rate.