Motorola Corporation

Allan Arthur Budlong

Joseph L Clark

Dan Huslig

Jeff Ricks Stripling

Kevin Gordon Brown

Randall J Samson

A received signal is sampled and a mean is calculated. A zero crossing sample is then located and used to locate a starting sample and the samples are read from that point forward, using sampling intervals and mean crossings, to decode the bit stream. Alternatively, first and second derivatives of the signal are calculated. A sign (.+-.) of the first derivative sample at the first zero crossing of the second derivative is used to determine the sign of a sample. The second derivative of the signal is then read, using sampling intervals and the sign of the first derivative, to decode the bit stream. In another alternative, samples are used to calculate a rolling average of the samples. The rolling average of the sample is compared to the sample to determine the logic value of the sample based upon whether the sample is above or below the rolling average.

Method for decoding a digital signal

A dual-mode transmitter (100) adjusts a signal's deviation level when switched between a wideband mode and a narrowband mode of operation. The transmitter (100) automatically attenuates the deviation of the signal based on a ratio of the maximum deviation level for the wideband mode to the maximum deviation for the narrowband mode utilizing wideband/narrowband maximum deviation adjust circuitry (115). Because the attenuation based on the ratio of the maximum deviation levels is too large for a narrowband mode signal having average deviation, the signal is amplified based on a ratio of the average deviation level for the wideband mode to the average deviation for the narrowband mode utilizing wideband/narrowband average deviation adjust circuitry (103). Attenuation and amplification of the signal's deviation occur when the dual-mode transmitter (100) is operating in the narrowband mode.

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Redmond, WA, United States of America

Allan Arthur Budlong