Abstract: A method for signal processing, receiving a time domain signal having a sample-rate Fs and generating N time domain signal bands, each having a bandwidth equal to Fs/N. Receiving the N signal bands and transforming a first time domain signal band to a frequency domain at a first resolution and a second time domain signal band to the frequency domain at a second resolution, where the first resolution may be different from the second resolution. Determining one or more first filter coefficients using the frequency domain components from the first signal band and one or more second filter coefficients using the frequency domain components from the second signal band. Transforming the first and second filter coefficients from the frequency domain to a time domain. Applying the first and second time domain filter coefficients to the first and second time domain signals, respectively.

Abstract: A receiver circuit is for processing a received signal which includes at least a first portion and a second portion which repeats the content of the first portion after a repeat interval. For example, the receiver may be for DVB-T signals using COFDM. Two correlation values are measured. The first is between the first portion of the received signal, delayed by the repeat interval plus a difference interval, and the second portion. The second is between the first portion of the received signal, delayed by the repeat interval minus a difference interval, and the second portion. Any difference between the correlation values represents a difference between the receiver sampling rate, and the required sampling rate, and can be used to adjust the receiver sampling rate.

Abstract: A multi-rate speech codec supports a plurality of encoding bit rate modes by adaptively selecting encoding bit rate modes to match communication channel restrictions. In higher bit rate encoding modes, an accurate representation of speech through CELP (code excited linear prediction) and other associated modeling parameters are generated for higher quality decoding and reproduction. To achieve high quality in lower bit rate encoding modes, the speech encoder departs from the strict waveform matching criteria of regular CELP coders and strives to identify significant perceptual features of the input signal. The encoder generates pluralities of codevectors from a single, normalized codevector by shifting or other rearrangement. As a result, searching speeds are enhanced, and the physical size of a codebook built from such codevectors is greatly reduced.

Abstract: A speech-coding system provides improved speech coding by injecting high-frequency noise into an output of a pulse codebook. A filtered noise is generated by passing a high frequency noise signal through a high pass filter. The filtered high frequency noise is injected into the pulse output of the codebook through convolution. The combined noise signal and pulse output generates a perceptually improved encoded speech signal.

Abstract: A method for preparing a speech signal for encoding comprises determining whether the spectral content of an input speech signal is representative of a defined spectral characteristic (e.g., a defined characteristic slope). A frequency specific filter component of a weighting filter is controlled based on the determination of the spectral content of the speech signal or/and its location in the encoder. A core weighting filter component of the weighting filter may be maintained regardless of the spectral content of the speech signal.

Abstract: A transmitter for a cellular phone comprising an antenna and being operable at a first radio frequency band and a second radio frequency band is disclosed. The transmitter comprises a first power amplifier and a second power amplifier, one of which is active at a time. The first power amplifier has an input for a first signal at the first radio frequency band, an input for a first control signal and a first output for an amplified first signal. The first output is connectable to the antenna. The second power amplifier has an input for a second signal at the second radio frequency band, an input for a second control signal and a second output for an amplified second signal. The second output is connectable to the antenna. The transmitter further comprises a single control module associated with the first and second outputs of the power amplifiers. The control module generates a control signal for the active power amplifier.

Abstract: A voltage upconverter circuit wherein a switching voltage regulator circuit is used to charge a capacitor from a battery during an idle interval of portable phone transmission and wherein the charged capacitor is thereafter switched in series with the battery voltage for supply to a load during signal transmission, resulting in a smaller, less expensive and more efficient voltage upconverter circuit.