FREQUENCY MODULATED SYNTHESIZER USING LOW FREQUENCY OFFSET MIXED VCO

摘要

improved frequency synthesizer (100) capable of producing a real dc frequency modulation without the need to adjust the frequency of the reference oscillator, dc. the synthesizer (100) includes a phase comparator (104) which compares the reference signal (102) to the return signal (112).the output of the phase comparator (104) is filtered and coupled to the main voltage controlled oscillator (vco) (108). a balanced mixer (200) mixes the image signals from the main two vco vco (108), and a step (300).the vco is a step (300) integrated vco out at low frequencies (e.g. 100 to 300 khz) (308), whose center frequency is controlled accurately.with the aid of an adaptation to a vco (204) that is controlled by a feedback loop and using a balanced mixer (200) for reducing the frequency of picture image in order to reduce or eliminate the need for filtering out of the mixer.the configuration of the edge in the loop of the synthesizer mixer, as well as any content from a residual image due to imperfect balance or power supply bushing carrier mixer is mitigated by the response of the loop. the output signal of the mixer (200) is locked to the phase comparator (104) after being divided by n in a separator (114).