Telecommunications – Receiver or analog modulated signal frequency converter – Local control of receiver operation
Patent
1994-07-19
1996-03-12
Eisenzopf, Reinhard J.
Telecommunications
Receiver or analog modulated signal frequency converter
Local control of receiver operation
455 76, 455307, 455340, 331 17, 333174, 333214, H03L 7099, H03H 1100, H04B 116
Patent
active
054993920
ABSTRACT:
A tunable filter (25) is described for use in loop control circuits. The filter (25) has a time constant which is determined by a resistor (40) and a capacitor. The capacitor is simulated by the series combination of an impedance converter (41) and a variable resistor, such as a field effect transistor (42). The resistance of the transistor (42) is determined by a control signal present on a control line (32) and the impedance converter (41) converts the resistance into an equivalent capacitive reactance. Therefore, the control signal on the control line (32) effectively controls the capacitance present at a node (43) and, in conjunction with the resistor (40), determines the time constant, and therefore the response time and bandwidth, of the filter (25). Multiple pole, lowpass, bandpass, highpass, and bandstop filters can be constructed. The impedance converter (41) uses a very small capacitor to simulate a large capacitance value at the node (43). This small capacitance value also allows the filter (25) to be fabricated as part of an integrated circuit.
REFERENCES:
patent: 3611168 (1971-10-01), Haggai
patent: 3657661 (1972-04-01), Jarger
patent: 3702405 (1972-11-01), Zwirn et al.
patent: 3835399 (1974-09-01), Holmes
patent: 4093824 (1978-06-01), GrosJean
patent: 4156195 (1979-05-01), GrosJean
patent: 4479091 (1984-10-01), Yoshisato
patent: 4736167 (1988-04-01), Kojima et al.
patent: 4970472 (1990-11-01), Kennedy et al.
patent: 5068626 (1991-11-01), Takagi et al.
patent: 5126692 (1992-06-01), Shearer et al.
patent: 5144156 (1992-09-01), Kawasaki
patent: 5392456 (1995-02-01), Mitomo et al.
Eisenzopf Reinhard J.
Matsushita Communication Industrial Corporation of America
Pham Chi H.
LandOfFree
Filter having a variable response time for filtering an input si does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Filter having a variable response time for filtering an input si, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Filter having a variable response time for filtering an input si will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2107876