Patent ID: 6727764
Filing Date: 2004-04-27
Classification: H03J,H03L

Abstract:
A radio frequency synthesizer system or generating device, of-generating a number of waveforms having an established relationship in phase, frequency and spectral components, suitable for use in a virtual local oscillator block of a homodyne receiver, said generating device comprising:a ring oscillator comprising J amplifiers (where J is an even integer of value six or more) connected in a serial fashion so that the output of each amplifier drives the input of the next amplifier, and the output of the last amplifier drives the input of the first amplifier; two combinations of logical gates each combining various outputs of the amplifiers of said ring oscillator to produce waveforms, one combination of gates driven by the outputs of the odd-numbered amplifiers (1, 3, . . . , J-3), a second combination of gates driven by the outputs of the even-numbered amplifiers (2, 4, . . . , J-2), a first non-inverting buffer driven by the output of the amplifier J-1 preceding the last amplifier J, and a second non-inverting buffer driven by the output of the last amplifier J, the two combinations of logical gates being matched for delay and arranged to produce signals such that the output from the odd numbered stages and the output from the even numbered stages bear the relationship required to be suitable for use in a virtual local oscillator block of a homodyne receiver; and means to ensure the frequency of said ring oscillator is stable within the limits required by said virtual local oscillator block. 2.The radio frequency synthesizer system or generating device of claim 1 wherein said amplifiers are balanced amplifiers.