Description

The TMC2242C, a linear-phase low-pass half-band digital filter with fixed coefficients, can be used to halve or double the sampling rate of a digital signal. When used as a decimating post-filter with a double-speed oversampling A/D converter, it greatly reduces the cost and complexity of the required analog antialiasing pre-filters. When used as an interpolating pre-filter with a double-speed oversampling D/A converter, it greatly reduces the complexity and cost of the necessary analog post-filter, particularly when its x/sin(x) correction filter is engaged.

Features

? Pin-compatible upgrade of TMC2242B

? User-selectable interpolate d.c. gain, 0 dB or -6 dB

? True unity d.c. gain in all “0 db” modes

? 40 MSPS performance in equal-rate filter modes

? 40 and 60 MSPS speed grades in all other modes

? User-selectable 2:1 decimation, 1:2 interpolation, and equal-rate filter modes, plus unfiltered bypass/delay mode

? Defeatable πx/sin(πx) compensation filter

? Passband ripple <0.014 dB

? Stopband rejection >56 dB

? Dedicated 12-bit two’s complement or unsigned input bus

? 16-bit two’s complement or unsigned output bus with user-selectable rounding to 8 to 16 effective bits

? Programmable limiter prevents overflow or clips to CCIR601 levels

? New double-latency modes match Y channel data flow to slower-sampled CB and CR data flows

? New dual-channel interpolation and decimation for YUV422

Applications

? Digital-to-Analog Converter Prefiltering with optional x/sinx correction

? 1:2 interpolation

? Analog-to-Digital Converter Postfiltering

? 2:1 decimation

? Low-ripple low-pass (0 to 0.2 fs) filter