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US 7,548,941 B2Granted
Digital filter using memory to emulate variable shift register
AssigneeAnalog Devices, Inc.
InventorMichael Hennedy
Life of this patent
Estimating the term…
Abstract
A digital filter uses memory to emulate a variable shift register. Data samples are stored in a memory. The data samples are read from the memory, multiplied with corresponding coefficients stored in the same or a different memory, logically shifted, and written back into the memory so as to emulate a variable shift register. The data samples can be logically shifted by one or more bits at a time.
Claims22
A digital filter comprising:
- at least one memory for storing a plurality of data samples and coefficients, the memory including distinct data input and output ports;
- a multiplier for multiplying data samples read from the at least one memory with corresponding coefficients read from the at least one memory;
- an accumulator for summing multiplier outputs;
- and
- control logic for controlling the at least one memory, the multiplier, and the accumulator, the control logic logically shifting a data sample read from the at least one memory via the data output port and writing the logically shifted data sample back into the at least one memory via the data input port so as to emulate a shift register, the distinct data input and output ports allowing a subsequent data sample to be read from the at least one memory and the shifted data sample to be written to the at least one memory substantially simultaneously.
2 more elements
Apparatus for digital filtering comprising:
- at least one memory for storing data samples and coefficients, the memory including distinct data input and output ports;
- means for combining data samples read from the at least one memory with corresponding coefficients read from the at least one memory;
- and
- means for logically shifting a data sample read from the at least one memory via the data output port and writing the logically shifted data sample back into the at least one memory via the data input port so as to emulate a shift register, the distinct data input and output ports allowing a subsequent data sample to be read from the at least one memory and the shifted data sample to be written to the at least one memory substantially simultaneously.
1 more element
A communication device comprising:
- a transceiver for transmitting and receiving communication signals;
- and
- a digital filter in communication with the transceiver for processing digitized data samples corresponding to the communication signals, wherein the digital filter includes:
- at least one memory for storing data samples and coefficients, the at least one memory including distinct data input and output ports;
- a multiplier for multiplying data samples read from the at least one memory with corresponding coefficients read from the at least one memory;
- an accumulator for summing multiplier outputs;
- and
- control logic for controlling the at least one memory, the multiplier, and the accumulator, the control logic logically shifting a data sample read from the at least one memory via the data output port and writing the logically shifted data sample back into the at least one memory via the data input port so as to emulate a shift register, the distinct data input and output ports allowing a subsequent data sample to be read from the at least one memory and the shifted data sample to be written to the at least one memory substantially simultaneously.
5 more elements
A method for digital filter comprising:
- reading a data sample and a corresponding coefficient from a first location in the at least one memory;
- combining the data sample and the corresponding coefficient;
- logically shifting the data sample;
- and
- writing the logically shifted data sample back into a second location in the at least one memory substantially simultaneously with reading a data sample from such second location, so as to emulate a shift register.
2 more elements
Dependencies are inferred from the claim text.