Abstract: A vehicle communication system uses one or more components to process both narrow band signals and spread spectrum signals. A spread spectrum-like signal is generated from the narrow band signal. The spread spectrum-like signal is processed as a spread spectrum signal.

Abstract: A vehicle communication system uses one or more components to process both narrow band signals and spread spectrum signals. A spread spectrum-like signal is generated from the narrow band signal. The spread spectrum-like signal is processed as a spread spectrum signal.

Abstract: A digital signal processing architecture for an audio system combines multiple functions in programmable and reconfigurable blocks to achieve an efficient use of hardware and chip area. AM, FM, and audio functions can be performed using the same reconfigurable hardware while taking into account the different sample rates and processing functions required for each.

Abstract: An adaptive bandwidth control system optimizes radio reception by controlling intermediate frequency bandwidth and baseband bandwidth to reduce both interference and noise while remaining compatible with AM broadcasts using the NRSC-1 standard. An adaptive IF filter detects the presence of interfering undesired sources. The IF bandwidth is narrowed if any interferers are detected. Simultaneously, the frequency content of the demodulated baseband signal is analyzed to control an optimal baseband bandwidth so that any frequencies containing substantially only noise are eliminated.

Abstract: A carrier-based signal is received from a tuner and is digitized to produce a digital intermediate frequency (IF) signal. Automatic gain control is applied to the carrier-based signal either prior to or after digitization. An adaptive intermediate frequency bandwidth control system detects IF signal level after channel filtering. The level is compared to a predetermined threshold having a value related to the known signal level of the AGC'ed signal which is being input to the channel filter in order to provide a measure of either 1) the presence of interfering adjacent channels, or 2) reception or a weak signal which can't be compensated for by AGC. The IF bandwidth is narrowed in either circumstance. Digital FIR or IIR filtering is used. The invention allows bandwidth switching to be done very quickly with minimal transient effects. A threshold value is selected depending upon the IF channel bandwidth being used at any given time.

Abstract: An adaptive intermediate frequency bandwidth control system detects IF signal levels both before and after channel filtering. The two levels are compared to provide a measure of the presence of interfering adjacent channels. This measure is compared to a programmable threshold and the IF bandwidth is narrowed if any interferers are detected. Digital FIR or IIR filtering is used. The invention allows bandwidth switching to be done very quickly with minimal transient effects. A difference threshold is selected depending upon the IF channel bandwidth being used at any given time.