Abstract: A system for controlling the gain of an input signal in an audio signal amplifier. The system includes a user-operable gain control, and analog and digital circuit elements that together are configured to modify the gain of the input signal in response to the user-operable gain control.

Abstract: A system for controlling the gain of an input signal in an audio signal amplifier. The system includes a user-operable gain control, and analog and digital circuit elements that together are configured to modify the gain of the input signal in response to the user-operable gain control.

Abstract: A method of branch metric calculation of trellis coded data, suitable for a decoder of phase angle on a carrier modulated with phase shift keying (PSK) modulation, begins with an expressing angles of phase shift by a vectorial representation of sectors within quadrants of a circle. The sectors are subdivided into sub-sectors of differing sizes, and the sub-sectors are divided further into equal increments of angle referred to as PIEs. The PIEs and the quadrants are identified and, in each quadrant, there is an assigning of a set of branch metrics to serve as identifiers of respective ones of the sub-sectors in each sector of the quadrant. The set of branch metrics in one sector of the quadrant differs from the set of branch metrics in another of the sectors of the quadrant by a permutation of the branch metrics. The phase data is outputted in the form of branch metrics and quadrant for use by a decoder such as a Viterbi decoder.

Abstract: This circuit permits M-sequence signals to be generated and decoded very fast while using relatively low power, low speed circuitry components.