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公开(公告)号：GB2137447B
公开(公告)日：1986-09-03
申请号：GB8407985
申请日：1984-03-28
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD
Abstract: A tuning system for a receiver includes an RF filter for selecting the RF signal corresponding to a selected channel of a plurality of channels in response to a filter tuning control signal, a local oscillator for developing an oscillator signal, the frequency of which is controlled by an oscillator tuning control signal developed in response to a binary coded representation of the channel number of the selected selection, and a mixer for heterodyning the selected RF signal with the local oscillator signal to produce an IF signal. A circuit including a memory is provided for storing binary signals for controlling the modification of the oscillator tuning control signal to derive the filter tuning control signal. Since the modification needed to derive the filter tuning control signal is the same for groups of channels, the number of memory locations is less than the total number of channels and the addresses are therefore generated by coupling means responsive to the coded channel signals for supplying only a predetermined number of bits of said coded channel number representative signal to the address inputs of the memory. Since the number of modifications needed from higher number channels is less than for lower number of channels, the coupling means ignores increasing numbers of least significant bits of the coded channel number representative signal for developing the address signals, as the channel number increases.
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公开(公告)号：DE3443628A1
公开(公告)日：1985-06-05
申请号：DE3443628
申请日：1984-11-29
Applicant: RCA CORP
Abstract: A multiplier for multiplying the modulated sound and picture carriers to produce an intercarrier sound signal in a quasi-parallel sound channel of an IF section has a pair of anti-parallel connected diodes in a limiter for generating an amplitude limited version of the picture carrier. It has been discovered that the varying capacitance of the diodes with picture amplitude can cause phase shifts and hence phase modulation interference in the intercarrier signal. The latter is especially troublesome for stereo sound reproduction. To reduce such interference, a low value resistor is shunt coupled to the diodes to inhibit the capacitance variations of the diodes and resulting undesired phase modulation in the intercarrier sound signal.
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公开(公告)号：GB2103445B
公开(公告)日：1985-03-27
申请号：GB8220835
申请日：1982-07-19
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD , WHITLEDGE GARY ALLEN
Abstract: The IF section of a television receiver includes an amplifier having an input terminal for receiving an IF signal and an output terminal at which an amplified version of the IF signal is developed and a SAW filter having two input terminals, one of which is connected to AC signal ground, for receiving the amplified IF signal and an output terminal for providing a modified IF signal having a bandpass characteristic determined by the SAW filter. An impedance transformation network is coupled between the output terminal of the amplifier and the input terminal of the SAW filter for increasing the effective load impedance of the amplifier and for decreasing the output impedance of the drive arrangement. The former aspect of the impedance transformation network allows a transistor with lower current supplying capabilities to be employed. The latter aspect of the impedance transformation network tends to reduce undesired voltages developed in response to reflections between the transducers of the SAW filter. Specifically, the impedance transformation network includes an inductor connected between the output terminal of the amplifier and the AC signal ground, a capacitor connected between the output terminal of the amplifier and the input terminal of the SAW filter and a resistor connected between the input terminal of the SAW filter and the AC signal ground. Desirably, the capacitance of the capacitor is in the same order of magnitude as the input capacitance of the SAW filter and the inductance of the inductor is selected to provide a resonance with the effective capacitance in the passband.
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公开(公告)号：DE3227087A1
公开(公告)日：1983-02-03
申请号：DE3227087
申请日：1982-07-20
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD
Abstract: The IF section of a television receiver includes an amplifier having an input terminal for receiving an IF signal and an output terminal at which an amplified version of the IF signal is developed and a SAW filter having two input terminals, one of which is connected to AC signal ground, for receiving the amplified IF signal and an output terminal for providing a modified IF signal having a bandpass characteristic determined by the SAW filter. An impedance transformation network is coupled between the output terminal of the amplifier and the input terminal of the SAW filter for increasing the effective load impedance of the amplifier and for decreasing the output impedance of the drive arrangement. The former aspect of the impedance transformation network allows a transistor with lower current supplying capabilities to be employed. The latter aspect of the impedance transformation network tends to reduce undesired voltages developed in response to reflections between the transducers of the SAW filter. Specifically, the impedance transformation network includes an inductor connected between the output terminal of the amplifier and the AC signal ground, a capacitor connected between the output terminal of the amplifier and the input terminal of the SAW filter and a resistor connected between the input terminal of the SAW filter and the AC signal ground. Desirably, the capacitance of the capacitor is in the same order of magnitude as the input capacitance of the SAW filter and the inductance of the inductor is selected to provide a resonance with the effective capacitance in the passband.
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公开(公告)号：FI75962B
公开(公告)日：1988-04-29
申请号：FI830993
申请日：1983-03-23
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD , EVANS ROBERT MICHAEL
Abstract: In a multi-band radio frequency tuning system, typified by a television tuning system including UHF and VHF signal paths (14,36,44), each such path is tuned by a tuning voltage (VT) and coupled to a common signal path (50,60) by a diplexer (20). In order to attenuate UHF signals so to not cause interferences with a VHF channel signal which has been selected, the UHF filter (14) is detuned when a VHF channel is selected. Detuning the UHF filter is accomplished by filter control (15) which modifies the tuning voltage (VT) for the UHF filter (14) responsive to the VHF band-switching voltage (VB 12). The filter 14 is described in detail (Figs. 3 or 4) and includes varactor diodes (CD42, CD44).
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Patent Agency Ranking
公开(公告)号：FR2541840B1
公开(公告)日：1988-03-11
申请号：FR8402955
申请日：1984-02-27
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD
Abstract: A tuning system for a receiver for providing an IF signal from a selected one of RF signals residing in a signal frequency band, comprises filter means for passing RF signals corresponding to a selected channel in response to a filter tuning control signal, mixing means responsive to the selected RF signals and a local oscillator signal for frequency translating the selected RF signals to develop a predetermined IF signal and a local oscillator for generating the local oscillator signal in response to an oscillator tuning control signal. A DC signal translating means includes an amplifier having an input responsive to the oscillator tuning control signal and having first and second predetermined gain transfer characteristics for modifying the oscillator tuning control signal and for providing at an output the filter tuning control signal. A switch means responsive to one of the tuning control signals changes the gain characteristic of the amplifier from the first characteristic to the second, so as to derive a piecewise-linear approximation of the filter tuning control signal from the oscillator tuning control signal.
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公开(公告)号：FI872790A
公开(公告)日：1987-12-31
申请号：FI872790
申请日：1987-06-23
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD
Abstract: A mixer for mixing first and second signals for providing a difference signal comprises a mixing transistor (200). The first and second signals are applied between the base and emitter electrodes of the transistor. A non-linear impedance (212) is coupled in series with the emitter electrode. Spurious signal components are reduced in amplitude compared with the difference signal.
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公开(公告)号：FI872790A0
公开(公告)日：1987-06-23
申请号：FI872790
申请日：1987-06-23
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD
Abstract: A mixer for mixing first and second signals for providing a difference signal comprises a mixing transistor (200). The first and second signals are applied between the base and emitter electrodes of the transistor. A non-linear impedance (212) is coupled in series with the emitter electrode. Spurious signal components are reduced in amplitude compared with the difference signal.
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公开(公告)号：FI70356C
公开(公告)日：1986-09-15
申请号：FI802659
申请日：1980-08-22
Applicant: RCA CORP
Inventor： GIBSON WALTER GOLD , LIU FRANK CHIH-SHING , MUTERSPAUGH MAX WARD
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公开(公告)号：GB2117588B
公开(公告)日：1985-11-27
申请号：GB8308098
申请日：1983-03-24
Applicant: RCA CORP
Inventor： MUTERSPAUGH MAX WARD , EVANS ROBERT MICHAEL
Abstract: In a multi-band radio frequency tuning system, typified by a television tuning system including UHF and VHF signal paths (14,36,44), each such path is tuned by a tuning voltage (VT) and coupled to a common signal path (50,60) by a diplexer (20). In order to attenuate UHF signals so to not cause interferences with a VHF channel signal which has been selected, the UHF filter (14) is detuned when a VHF channel is selected. Detuning the UHF filter is accomplished by filter control (15) which modifies the tuning voltage (VT) for the UHF filter (14) responsive to the VHF band-switching voltage (VB 12). The filter 14 is described in detail (Figs. 3 or 4) and includes varactor diodes (CD42, CD44).
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