Rom-based finite impulse response filter for use in mobile telephone

摘要: The finite impulse response (FIR) filter (20) is implemented as a table (104) using read-only memory (ROM). FIR stores pre-calculated output value for each permissible combination of input values (102) to be filtered. Streams are successively shifted into the shift register (106) and corresponding output. telephone employs data burst randomizer (18) provide signal composed sequences null or 0 antipodal (+1's -1's). Hence, combinations include only patterns containing either all signals, leading signals followed by trailing signals. look up configured exploit these limitations on streams yielding having relatively few entries.