Other

Jon C Dattorro

David Andreas

J William Mauchly

Albert J Charpentier

A digital signal processor for efficiently handling audio applications is disclosed. The single chip digital signal processor includes an on-chip instruction memory for outputting instructions representing an audio application program. Four busses, W, X, Y and Z, provide communication within the processor. An ALU performs a plurality of arithmetic and logical functions according to the instruction memory. Specialized implementations for functions have been specially developed for audio applications, for example, a single cycle average instruction, a jump on condition code instruction, a repeat instruction, a limit instruction. A Multiplier Accumulator/Barrel Shifter performs a plurality of MAC and shifting functions according to the instruction memory. The MAC/BS is coupled in parallel with the ALU and an Address Generator. The Address Generator performs a plurality of address calculation functions according to the instruction memory. Some of the data storage areas include: 1) a GPR memory for writing data to the X and Y busses and reading data from the Z bus; 2) an AOR memory for writing data to the W, X, and Y busses and reading data from the Z bus; and 3) an SPR memory for writing data to and reading data from the X, Y and Z busses and for outputting control information to the ALU, the MAC/BS and the AGEN.

Digital signal processor for audio applications

A single stage multi-rate finite impulse response filter is used as the decimating filter for a sigma-delta analog-to-digital converter. The filter uses 2048 22-bit coefficient values to produce a sampled data output signal having a sampling rate of 48 KHz and a sample resolution of 16 bits from an input signal having a sampling rate of 3.072 MHz and a sample resolution of one bit. The filter uses a single read-only memory to hold the 2048 coefficient values. The coefficient values are distributed to eight four-way multiplexed accumulators by a circuitry which includes a signal multiplexer and a barrel shifter. The accumulators use unsigned arithmetic to calculate the output sample values. A value C0, representing a normalizing offset and gain applied to each of the coefficient values, is selected such that 2048 times C0 is a value which overflows the accumulator, leaving a value of zero in the accumulator.

Growing community of inventors

Devon, PA, United States of America

Jon C Dattorro