Abstract: A noise reduction device according to an aspect of an embodiment includes a detection unit, a calculation unit, and a reduction unit. The detection unit detects frequency components of a plurality of noise signals that are included in a received signal, based on a frequency spectrum of the received signal. The calculation unit calculates a coefficient, based on the frequency components that are detected by the detection unit. The reduction unit reduces n noise signals that are at least a part of the plurality of noise signals from the received signal, depending on the coefficient that is calculated by the calculation unit (where n is a positive number that is greater than or equal to 2).

Abstract: A noise reduction device according to an aspect of an embodiment includes a detection unit, a calculation unit, and a reduction unit. The detection unit detects frequency components of a plurality of noise signals that are included in a received signal, based on a frequency spectrum of the received signal. The calculation unit calculates a coefficient, based on the frequency components that are detected by the detection unit. The reduction unit reduces n noise signals that are at least a part of the plurality of noise signals from the received signal, depending on the coefficient that is calculated by the calculation unit (where n is a positive number that is greater than or equal to 2).

Abstract: A receiving apparatus comprising: a frequency-fluctuation-detection unit to detect a frequency difference between a received and desired signals; a first-undesired-level-detection unit to output as a first-undesired level an amplitude-level-difference between the signals having passed through first-and-second-band-pass filters in the received signals; one or a plurality of second-undesired-level-detection units to output amplitude levels of signals having passed through third-and-fourth-band-pass filters in the received signals as second-and-third-undesired levels, respectively, and output a sum of the second-and-third-undesired levels as a fourth-undesired level; and a determination unit to determine whether an undesired state, where an adjacent-undesired signal is present, occurs according to the fourth-undesired level if an absolute value of the frequency difference is equal to or greater than a predetermined-reference value, and select any one of the first-to-third-undesired levels to be outputted accordi

Abstract: A receiving apparatus comprising: a first mixing unit to output first and second mixed signals each having a first frequency that is a frequency difference between a received signal and a first local oscillator signal, the first and second mixed signals having phases substantially orthogonal to each other; a phase control unit to output second and third local oscillator signals each having a second frequency, the second and third local oscillator signals having a phase difference from each other corresponding to a phase difference between the first and second mixed signals; and a second mixing unit to add a signal obtained by mixing the first mixed signal and the second local oscillator signal, and a signal obtained by mixing the second mixed signal and the third local oscillator signal, to output an intermediate frequency signal having an intermediate frequency that is a difference between the first and second frequencies.

Abstract: A noise canceller is constituted by a forward linear prediction processor that performs forward linear prediction for a reception signal in a noisy section where the reception signal includes noise, and a backward linear prediction processor that performs backward linear prediction for the reception signal in the noisy section. A signal generator generates a replacement signal, to replace the reception signal in the noisy section, based on the forward linear prediction values obtained by the forward linear prediction and the backward linear prediction values obtained by the backward linear prediction. The signal generator obtains replacement values for a plurality of points within the noisy section by weighting the corresponding forward prediction value and the corresponding backward prediction value with an internal division ratio, the internal division ratio having a linear or nonlinear functional relationship to the time axis of the signal.

Abstract: A receiving apparatus comprising: a frequency-fluctuation-detection unit to detect a frequency difference between a received and desired signals; a first-undesired-level-detection unit to output as a first-undesired level an amplitude-level-difference between the signals having passed through first-and-second-band-pass filters in the received signals; one or a plurality of second-undesired-level-detection units to output amplitude levels of signals having passed through third-and-fourth-band-pass filters in the received signals as second-and-third-undesired levels, respectively, and output a sum of the second-and-third-undesired levels as a fourth-undesired level; and a determination unit to determine whether an undesired state, where an adjacent-undesired signal is present, occurs according to the fourth-undesired level if an absolute value of the frequency difference is equal to or greater than a predetermined-reference value, and select any one of the first-to-third-undesired levels to be outputted accordi

Abstract: A receiving apparatus comprising: a frequency conversion unit configured to convert a received radio frequency signal to an intermediate frequency signal; an automatic gain control unit configured to control an amplitude level of at least either one of the radio frequency signal and the intermediate frequency signal according to a gain control signal; a demodulation unit configured to demodulate an audio signal from the intermediate frequency signal; a correction level output unit configured to output a correction level signal corresponding to a difference between a demodulation unit input level and a predetermined reference level, the demodulation unit input level being an amplitude level of the intermediate frequency signal inputted to the demodulation unit; and an addition unit configured to add the gain control signal and the correction level signal, to be outputted as a signal strength signal indicating received signal strength of the radio frequency signal.

Abstract: An AM receiving circuit is disclosed which comprises an intermediate frequency amplifying unit that generates an intermediate frequency signal from a broadcast wave signal received by an antenna to amplify and output the intermediate frequency signal; an AGC (Automatic Gain Control) unit that sets gain of the intermediate frequency amplifying unit depending on electric field intensity of the broadcast wave signal; and an AM detecting unit that detects the intermediate frequency signal output from the intermediate frequency amplifying unit, wherein the AM receiving circuit comprises a sound quality compensating unit including: a filter unit that extracts a predetermined frequency band of the audio signal; an amplifying unit that boosts or attenuates the audio signal in the predetermined frequency band extracted from the filter unit; and a controlling unit that controls filter characteristics of the filter unit and sets a boosting function or an attenuating function of the amplifying unit, depending on the elec

Abstract: A receiving apparatus comprising: a first mixing unit to output first and second mixed signals each having a first frequency that is a frequency difference between a received signal and a first local oscillator signal, the first and second mixed signals having phases substantially orthogonal to each other; a phase control unit to output second and third local oscillator signals each having a second frequency, the second and third local oscillator signals having a phase difference from each other corresponding to a phase difference between the first and second mixed signals; and a second mixing unit to add a signal obtained by mixing the first mixed signal and the second local oscillator signal, and a signal obtained by mixing the second mixed signal and the third local oscillator signal, to output an intermediate frequency signal having an intermediate frequency that is a difference between the first and second frequencies.

Abstract: A signal processing circuit is disclosed which comprises: an attenuating unit that attenuates a demodulated signal acquired by detecting a received signal; a detecting unit that detects a first signal indicating intensity of the demodulated signal; and an attenuation rate setting unit that sets an attenuation rate of the attenuating unit based on the first signal, wherein the attenuation rate setting unit sets the attenuation rate of the attenuating unit depending on: at least one signal of a second signal indicating a change in an envelope curve acquired based on an intermediate frequency signal of the received signal and a third signal indicating electric field intensity acquired based on the intermediate frequency signal; and the first signal.

Abstract: A noise eliminating circuit is disclosed which comprises a noise elimination processing unit that interpolates a generation period of pulse noise overlapped with a received signal depending on a first detection signal acquired by level detection of an intermediate frequency signal of the received signal, the first detection signal indicating the generation of the pulse noise, wherein the noise eliminating circuit comprises: a predicting unit that predicts a value of the intermediate frequency signal at a predetermined clock time based on an intermediate frequency signal generated a predetermined time earlier than the intermediate frequency signal; a detecting unit that compares a difference between the value of the predicted intermediate frequency signal and the value of the generated intermediate frequency signal, at the predetermined clock time, with a predetermined threshold, to output a second detection signal indicating the generation of the pulse noise; and a noise elimination controlling unit that sele

Abstract: A signal processing circuit is disclosed which comprises: an attenuating unit that attenuates a demodulated signal acquired by detecting a received signal; a detecting unit that detects a first signal indicating intensity of the demodulated signal; and an attenuation rate setting unit that sets an attenuation rate of the attenuating unit based on the first signal, wherein the attenuation rate setting unit sets the attenuation rate of the attenuating unit depending on: at least one signal of a second signal indicating a change in an envelope curve acquired based on an intermediate frequency signal of the received signal and a third signal indicating electric field intensity acquired based on the intermediate frequency signal; and the first signal.

Abstract: A raw signal is delayed in a delay circuit (1) and then supplied to one of the input terminals of a selection circuit (8). The raw signal is also supplied to another delay circuit (2) to be delayed. Subsequently, data of this delayed signal is processed by spline interpolation in an interpolation circuit (4), and the interpolation values are supplied to the other of the input terminals of the selection circuit (8). Further, a timer (7) is operated according to an output signal from a noise detection circuit (6) which detects noise in the raw signal. When noise is detected, the selection circuit (8) switches to select the output from the interpolation circuit (4), thereby achieving interpolation of noisy sections.

Abstract: A signal processing circuit for a tuner has a detector band pass filter for extracting a carrier of an intermediate frequency signal, a frequency counter for counting, based on a clock signal, a frequency of a carrier of the intermediate frequency signal which passes through the detector band pass filter, and an intermediate frequency variation signal outputting section for outputting an intermediate frequency variation signal based on a difference between the counted frequency and a frequency of the clock signal. Based on the intermediate frequency variation signal, a frequency selection characteristic of an intermediate frequency band pass filter, a signal detector, an adjacent interference detector, or an S-meter-band pass filter are controlled.

Abstract: If a mode calculating section (52) judges that an inputted modulated signal is nearly in a no-sound state, the interpolation width determined by an interpolation width calculating section (53) is increased, whereas if the mode calculating section (52) judges that the inputted modulated signal contains a lot of high-frequency components, the interpolation width determined by the interpolation width calculating section (53) is decreased.

Abstract: An AM receiving circuit is disclosed which comprises an intermediate frequency amplifying unit that generates an intermediate frequency signal from a broadcast wave signal received by an antenna to amplify and output the intermediate frequency signal; an AGC (Automatic Gain Control) unit that sets gain of the intermediate frequency amplifying unit depending on electric field intensity of the broadcast wave signal; and an AM detecting unit that detects the intermediate frequency signal output from the intermediate frequency amplifying unit, wherein the AM receiving circuit comprises a sound quality compensating unit including: a filter unit that extracts a predetermined frequency band of the audio signal; an amplifying unit that boosts or attenuates the audio signal in the predetermined frequency band extracted from the filter unit; and a controlling unit that controls filter characteristics of the filter unit and sets a boosting function or an attenuating function of the amplifying unit, depending on the elec

Abstract: A noise canceller is constituted by a forward linear prediction processor that performs forward linear prediction for a reception signal in a section where the reception signal includes noise, a backward linear prediction processor that performs backward linear prediction for the reception signal in the section, and a signal generator that generates a replacement signal, which is a signal replacing the reception signal in the section, based on the forward linear prediction values obtained by the forward linear prediction and the backward linear prediction values obtained by the backward linear prediction.

Abstract: An AM receiver circuit comprises an IF intensity detection section which detects intensity of a carrier wave of an IF signal and outputs an IF signal carrier wave intensity signal in accordance with the detected intensity. The IF intensity detection section extracts the carrier wave frequency component of the IF signal using a BPF, and converts the extracted intensity of the IF signal carrier wave intensity into a direct current signal using an integrator, to thereby obtain the IF signal carrier wave intensity signal. A sound compensation section, which serves to compensate sound quality of an audio signal output from an AM detection section, performs sound quality compensation based on the IF signal carrier wave intensity signal when the received field intensity is low. In this manner, appropriate sound quality compensation can be performed even when the received broadcast wave field intensity is low.

Abstract: A signal processing circuit for a tuner has a detector band pass filter for extracting a carrier of an intermediate frequency signal, a frequency counter for counting, based on a clock signal, a frequency of a carrier of the intermediate frequency signal which passes through the detector band pass filter, and an intermediate frequency variation signal outputting section for outputting an intermediate frequency variation signal based on a difference between the counted frequency and a frequency of the clock signal. Based on the intermediate frequency variation signal, a frequency selection characteristic of an intermediate frequency band pass filter, a signal detector, an adjacent interference detector, or an S-meter-band pass filter are controlled.

Abstract: An AM receiver circuit comprises an IF intensity detection section which detects intensity of a carrier wave of an IF signal and outputs an IF signal carrier wave intensity signal in accordance with the detected intensity. The IF intensity detection section extracts the carrier wave frequency component of the IF signal using a BPF, and converts the extracted intensity of the IF signal carrier wave intensity into a direct current signal using an integrator, to thereby obtain the IF signal carrier wave intensity signal. A sound compensation section, which serves to compensate sound quality of an audio signal output from an AM detection section, performs sound quality compensation based on the IF signal carrier wave intensity signal when the received field intensity is low. In this manner, appropriate sound quality compensation can be performed even when the received broadcast wave field intensity is low.