Telecommunications – Receiver or analog modulated signal frequency converter – Noise or interference elimination
Patent
1990-01-24
1992-10-27
Eisenzopf, Reinhard J.
Telecommunications
Receiver or analog modulated signal frequency converter
Noise or interference elimination
333176, 333246, 455266, 455340, H04B 110
Patent
active
051597110
ABSTRACT:
A TVRO receiver for receiving frequency-modulated video signals comprises a tuner including a super-heterodyne circuit having a voltage-controlled oscillator (VCO), means for supplying a cotnrolling input voltage to the VCO, and a mixer for combining incoming 1st intermediate frequency (IF) sigals within a 1st predetermined IF frequency range with the output of the VCO to reduce the frequency of the 1st IF signals to generate 2nd IF signals within a 2nd predetermined IF frequency range, and a filter for selectively rejecting undersired interference signals. The interference filter comprises separate trap means for respectively blocking out interfering signals having selected bottom and top trap frequencies, tuning means for adjusting the bottom and top trap frequencies, means for increasing the quality factor of the trap means, and means for selectively switching the trap means into and out of the receiver based on the presence or absence of signals which interfere with the received signals.
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Vizmuller, "An Absorptive Notch Filter", RF Featured Technology RF, Jul. 1988, pp. 31-35.
Cheong Chung W.
Ma John Y.
Astec International Limited
Eisenzopf Reinhard J.
Pham Chi H.
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