Abstract: A synthesizer includes: a synthesizer unit that outputs an oscillation signal based on a reference oscillation signal; a temperature detecting unit that detects a temperature; a time variation detecting unit that detects a time variation in frequency of the reference oscillation signal based on a result of temperature detection by the temperature detecting unit; and a control unit that adjusts a frequency of the oscillation signal outputted from the synthesizer unit based on a result of detection by the time variation detecting unit. With such a configuration, frequency compensation control is performed on a transducer having a large temperature coefficient.

Abstract: A broadcast module includes a receiver for selecting the signal of a specific channel from the signals of a plurality of channels under control of a controller; a demodulator connected to the output of the receiver; a detector for detecting the signal-to-noise ratio of the signal selected by the receiver; and a comparator for comparing the signal-to-noise ratio detected by the detector with a predetermined level. The broadcast module can reduce the time required to specify a viewable channel.

Abstract: A frequency synthesizer receives a frequency compensation signal and a reference oscillation signal from an outside, and outputs first and second signals to an outside. The reference oscillation signal has a varying frequency. The frequency synthesizer includes an oscillator for generating the first signal based on the reference oscillation signal, and a frequency divider/multiplier for outputting the second signal by frequency-dividing or frequency-multiplying the first signal. The varying frequency of the first signal is compensated by the frequency compensation signal. This frequency synthesizer suppresses frequency variations of the first and second signals even if the reference oscillation signal has a large frequency variation.

Abstract: An OFDM reception device includes: a first channel estimation unit for estimating a channel distortion by using a signal that is supplied from the reception unit and has a first time interval; a second channel estimation unit for estimating a channel distortion by using a signal that is supplied from the reception unit and has a second time interval shorter than the first time interval; a selection unit for selecting and outputting one of a signal from the first channel estimation unit and a signal from the second channel estimation unit, according to a control signal from the control unit; and a correction unit for correcting a reception signal supplied from the reception unit, according to the channel estimation signal from the selection unit. The control unit determines the control signal to be supplied to the selection unit, according a reception state of the reception unit.

Abstract: A receiver according to the present invention includes a first receiving (RCV) quality detector and a second RCV quality detector connected before a combining unit. The second RCV quality detector determines a quality of a signal output from at least one of a first receiving unit and a second receiving unit by a method different from that of the first RCV quality detector. A controller allows the receiver to operate in a single receiving mode when a determination result of the second RCV quality detector is not better than a predetermined level regardless of a determination result of a determination result of the first RCV quality detector not being a predetermined level. When the receiver passes in an area where the receiver cannot receive a broadcast signal, the determination result of the second RCV quality detector is not better than the predetermined level. In response, the controller allows the receiver to operate in the single receiving mode, thereby reducing power consumption of the receiver.

Abstract: A receiver includes an oscillator for generating a local oscillator signal, a frequency converter for heterodyning a received signal of one frequency band or a plurality of frequency bands into an intermediate frequency (IF) signals with using the local oscillator signal, a filter connected to an output of the frequency converter and having a cut-off frequency changeable, an analog-digital (AD) converter connected to an output of the filter to convert an analog signal of one frequency band or a plurality of frequency bands into a digital signal, a pre-stage detector connected to an output of the AD converter or connected between the filter and the AD converter to detect a signal level, and a controller for controlling the cut-off frequency of the filter based on the signal level detected by the pre-stage detector.

Abstract: A synthesizer includes a synthesizer unit for generating a local oscillation signal based on a reference oscillation signal output from a reference oscillation unit including a MEMS resonator, a frequency fluctuation detector for detecting a frequency fluctuation of the MEMS resonator, and a frequency adjuster for adjusting a frequency of the local oscillation signal based on the frequency fluctuation detected by the frequency fluctuation detector. This synthesizer can output a signal with a stable frequency, even when an MEMS resonator demonstrating a large fluctuation in an oscillation frequency to temperatures is used.

Abstract: A synthesizer of the present invention includes a synthesizer section that generates an oscillation signal based on a reference oscillation signal output from a MEMS resonator and inputs the oscillation signal to a frequency converter; and a control section that adjusts a frequency of the oscillation signal output from the synthesizer section. In frequency adjustment by the control section, when a frequency adjustment unit of the synthesizer section is defined as predetermined value F in which quality of an output signal from the frequency converter is a quality limit threshold value, frequency adjustment unit ?fcont of the synthesizer section is within predetermined value F.

Abstract: A synthesizer including an oscillator for outputting an oscillation signal based on an output signal from a comparator, a frequency divider for dividing a frequency of an output signal from the oscillator based on control from a controller, and a temperature sensor for detecting an error between a preset frequency and a frequency based on a reference oscillation signal. The comparator compares an output signal from the frequency divider with an output signal from a MEMS oscillator and outputs a signal indicating the comparison result to the oscillator. The controller changes the frequency division ratio of the frequency divider based on an output signal from the temperature sensor and changes the frequency division ratio in a state in which the frequency division ratio is kept at the past value. Thus, phase noise deterioration in the synthesizer can be suppressed.

Abstract: In a digital broadcast receiver, when a bit error rate (BER) is larger than a threshold in a BER determining part, power is supplied to a first tuner and a second tuner for diversity reception. When the BER is smaller than the threshold, power supply to one of the first tuner and the second tuner is stopped for single reception. This structure allows power supply to one of the tuners to be stopped in excellent reception environments, thus reducing power consumption.

Abstract: The demodulator in the receiving module of the invention supplies a signal produced based on a signal level detected by a first detector to a second amplifier as an amplification degree adjustment signal. With this arrangement, when a second receiver works, an AGC voltage supplied to the second receiver is already close to an ultimately converging certain value. The AGC voltage supplied to the second receiver is thus stabilized in its value, from the value close to the ultimately converging certain value to the certain value. Accordingly, a time period required from the second receiver starts working until the AGC voltage supplied to second amplifier ultimately converges into the certain value is shortened.

Abstract: An oscillator unit is configured such that a frequency adjustment unit of a synthesizer used by a controller is smaller than a frequency variation tracking capability of a demodulator connected to an output side of a frequency converter. This structure successfully combines the temperature compensation control of an oscillator unit and the receiving process of a high-frequency receiving device. Accordingly, an oscillator unit with large temperature coefficient is applicable to high-frequency receiving devices.

Abstract: If receiving circuit is in a high-sensitivity mode, receiving circuit is switched to a low-sensitivity mode when the BER according to BER measurement circuit becomes more favorable than a release threshold. If receiving circuit is in the low-sensitivity mode, receiving circuit is switched to the high-sensitivity mode when the BER according to BER measurement circuit becomes more adverse than a start-up threshold. If switching between the high-sensitivity and low-sensitivity modes occurs, control is exercised so that switching from the high-sensitivity mode to the low is resistant to occurring, thereby suppressing the occurrence of a reception error caused by switching between the receiving modes.

Abstract: When performing switching control of reception modes trading off reception sensitivity against power consumption in a reception environment, the receiving apparatus and control method of the present invention perform state transition without a reception error occurring due to switching control with the aid of a reception mode in which an intermediate reception performance is provided. The present invention is particularly useful to balance the reception performance with the battery duration in a battery-powered, portable receiving terminal such as a television receiver for a mobile terminal.

Abstract: A receiver according to the present invention includes a first receiving (RCV) quality detector and a second RCV quality detector connected before a combining unit. The second RCV quality detector determines a quality of a signal output from at least one of a first receiving unit and a second receiving unit by a method different from that of the first RCV quality detector. A controller allows the receiver to operate in a single receiving mode when a determination result of the second RCV quality detector is not better than a predetermined level regardless of a determination result of a determination result of the first RCV quality detector not being a predetermined level. When the receiver passes in an area where the receiver cannot receive a broadcast signal, the determination result of the second RCV quality detector is not better than the predetermined level. In response, the controller allows the receiver to operate in the single receiving mode, thereby reducing power consumption of the receiver.

Abstract: A receiving apparatus includes a first receiver, a second receiver, a received signal synthesizer connected to the first and second receivers, a synchronizing signal synthesizer connected to the first and second receivers, and a synchronization detector connected to the synchronizing signal synthesizer. In this structure, synchronization determination is performed using a synchronizing signal of either the first or second receiver, and diversity reception is performed using the received signals of the first and second receivers.

Abstract: An OFDM reception device includes: a first channel estimation unit for estimating a channel distortion by using a signal that is supplied from the reception unit and has a first time interval; a second channel estimation unit for estimating a channel distortion by using a signal that is supplied from the reception unit and has a second time interval shorter than the first time interval; a selection unit for selecting and outputting one of a signal from the first channel estimation unit and a signal from the second channel estimation unit, according to a control signal from the control unit; and a correction unit for correcting a reception signal supplied from the reception unit, according to the channel estimation signal from the selection unit. The control unit determines the control signal to be supplied to the selection unit, according a reception state of the reception unit.

Abstract: In digital broadcast receiver (100), when a bit error rate (BER) is larger than a threshold in BER determining part (109), power is supplied to tuner (103) and tuner (104) for diversity reception. When the BER is smaller than the threshold, power supply to one of tuner (103) and tuner (104) is stopped for single reception. This structure allows power supply to one of the tuners to be stopped in excellent reception environments, thus reducing power consumption.

Abstract: The demodulator in the receiving module of the invention supplies a signal produced based on a signal level detected by a first detector to a second amplifier as an amplification degree adjustment signal. With this arrangement, when a second receiver works, an AGC voltage supplied to the second receiver is already close to an ultimately converging certain value. The AGC voltage supplied to the second receiver is thus stabilized in its value, from the value close to the ultimately converging certain value to the certain value. Accordingly, a time period required from the second receiver starts working until the AGC voltage supplied to second amplifier ultimately converges into the certain value is shortened.

Abstract: A broadcast module includes a receiver for selecting the signal of a specific channel from the signals of a plurality of channels under control of a controller; a demodulator connected to the output of the receiver; a detector for detecting the signal-to-noise ratio of the signal selected by the receiver; and a comparator for comparing the signal-to-noise ratio detected by the detector with a predetermined level. The broadcast module can reduce the time required to specify a viewable cannel.