PLL circuit having a low-pass passive filter coupled to a varact

Details PLL circuit having a low-pass passive filter coupled to a varact PLL circuit having a low-pass passive filter coupled to a varact

1994-11-29

1996-08-20

Faile, Andrew

Telecommunications

Receiver or analog modulated signal frequency converter

Signal selection based on frequency

4551804, 4551912, 455260, 455142, 455144, 331 17, H04B 106

Patent

active

055488293

ABSTRACT:
A low-pass passive filter is inserted in the phase locked loop of a voltage-controlled oscillating circuit having a varactor diode. The filter has a first resistor, a capacitor and a second resistor connected in that order and the blocking characteristics of the filter are changed in accordance with a selected value of the second resistor. A push-pull output circuit in which the upstream transistor is connected directly to the supply voltage line receives the signal from a phase comparator circuit (which is indicative of the result of phase comparison) and outputs it to the low-pass passive filter. The low-pass passive filter controls the terminal voltage of the varactor diode in accordance with the terminal voltage of the capacitor and the value of the second resistor is selected depending on the desired blocking characteristics of the filter.

REFERENCES:
patent: 4774480 (1988-09-01), Sato et al.
patent: 5146187 (1992-09-01), Vandegraaf
patent: 5153530 (1992-10-01), Takagi et al.
patent: 5220294 (1993-06-01), Ichikawa
"Wakaru PLL no Oyo Tekunikku (Applied Techniques of the PLL Circuit)", ed. by S. Takamatsu, Jan. 20, 1988.

Affiliated with

Also associated with

Rating

PLL circuit having a low-pass passive filter coupled to a varact does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with PLL circuit having a low-pass passive filter coupled to a varact, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and PLL circuit having a low-pass passive filter coupled to a varact will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2338680