Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Sanae Asayama

Atsuhito Terao

Masanori Suzuki

Koji Nakatsuji

Hiroaki Ozeki

Masaaki Noda

Hitonobu Furukawa

Masashi Yasuda

Yoshihide Tabata

Hideji Takami

Hirochika Kashima

Kazutoshi Sato

A high-frequency receiver and a portable device using the same receiver are proposed for reducing power consumption. Image interference determiner () determines whether or not image interference exists at the present position in a desirable channel to be received, which channel is obtained by a receiving section () or a GPS receiver (). Power supply control circuit () switches mixer () from an image rejection mixer to a double balance mixer when determiner () determines no image interference involves. This mechanism allows mixer () to work as the double balance mixer circuit during the reception of channels free from image interference, so that a mixer consuming less power is achievable. When mixer () works as the image rejection mixer circuit, image interference can be reduced.

High-frequency receiver and portable device using the same

A radio-frequency (RF) receiver includes an input terminal for receiving RF signals in a first frequency band and a second frequency band lower than the first frequency band, a first tuned filter allowing a signal of a passing frequency in the RF signal in the first frequency band to pass through the filter, a local oscillator, a frequency divider for frequency-dividing a signal output from the local oscillator, a first mixer operable to convert the signal output from the first tuned filter into a signal of an intermediate frequency, a second tuned filter allowing a signal of a passing frequency of the RF signal in the second frequency band to pass through the filter, a second mixer operable to convert the signal output from the second tuned filter into a signal of the intermediate frequency, and a phase-locked-loop (PLL) circuit operable to control an oscillation frequency of the local oscillator and the passing frequencies of the first tuned filter and the second tuned filter.

Radio-frequency receiver

A high frequency receiver of the present invention has a mixer of which one input part is connected to an output part of a filter and the other input part is connected to an output part of a frequency-variable local oscillator, and an output terminal connected to an output part of the mixer. The mixer is an image rejection mixer. The filter has a moderated damping characteristic in a frequency where the image rejection mixer reduces an image. Therefore, a high performance filter is not required, and hence a low price is realized.

High frequency receiver

Radio-frequency receiver and integrated circuit for use in receiver

An oscillation frequency changing means is inserted between a tuner and an oscillator of local oscillator () of a high frequency receiving device, and the oscillation frequency changing means, in each frequency band received, changes the oscillation frequency characteristic of local oscillator () in relation to the tuning voltage supplied from PLL circuit (), and operates in accordance with the frequency characteristic of tuning filter () to obtain an oscillation signal varied just by a predetermined frequency, thereby making it possible to receive broadband channels of continuous VHF broadcast band and UHF broadcast band.

High frequency receiving device, integrated circuit used for the same, and TV receiver using them

A mixer circuit can suppress image interfering signals and interfering signals related to higher harmonic component of an oscillator. Using the mixer circuit, it is possible to provide a high-frequency signal receiver which maintains good signal receiving condition. This mixer circuit comprises a plurality of mixers, oscillators, a plurality of oscillator phase shifters which serve to phase-shift the output of the oscillators and supply the output to the mixers, and a plurality of intermediate frequency phase shifters which serve to phase-shift the output of the mixers. The high-frequency signal receiver comprises at least a pre-filter and the mixer circuit.

Mixer circuit and high frequency signal receiver using the same

A receiver is operable even if including a local oscillator generating a signal at high frequencies but not in a wide frequency range. The receiver includes: a first frequency converter for mixing a received signal with a first local oscillation signal to convert the received signal into respective signals of plural first intermediate frequencies corresponding to a frequency of the received signal; and a second frequency converter for converting the signals of the first intermediate frequencies into a signal of a second intermediate frequency.

High-frequency signal receiver

An electronic tuner has an input terminal, a mixer receiving the signal fed into the input terminal, a matching circuit connected to an output of the mixer, a band-pass filter connected to an output of this matching circuit, an intermediate-frequency (IF) amplifier connected to an output of the band-pass filter, and an output terminal receiving output of the IF amplifier. These circuits are composed of balanced circuits and connected by balanced lines. The mixer has a high output impedance. For the matching circuit, the impedance of the matching circuit at the band-pass filter side is equal to the impedance of the band-pass filter at the matching circuit side. This structure can realize an electronic tuner having low power consumption.

Growing community of inventors

Aichi, Japan

Sanae Asayama