GF9101, GF9102A, GF9102A/L4A0915

The GF9101 is a high performance multirate digital filter which can be programmed to implement a wide range of signal processing functions using both symmetrical and asymmetrical filter structures. It is composed of a 12-tap FIR filter with internal RAM to hold up to 108 individual filters. An externally controlled address bus selects one of the 108 filters in each clock cycle. Pipelined architecture allows cascading of up to three devices with no additional hardware.

Two 10-bit input shift registers are provided for multiplexed filtering applications. The 12-bit coefficients can be programmed in serial, high speed parallel or microprocessor modes. In the high speed parallel mode,any one of the 108 filters can be reprogrammed in 18 clock cycles.

The GF9102A is a linear phase FIR digital filter that is usable in a variety of video signal processing applications. The evice contains three separate fixed coefficient filters and can be operated in three basic modes: 53 tap low pass filter, 9 tap chroma bandpass filter or 21 tap chroma bandpass filter.

In the 53 tap low pass filter mode, the GF9102A can replace the TMC2242 in all applications, except those requiring 1:1 low pass filtering, for improved performance and full CCIR 601 compatibility. Specific improvements include true unity gain at DC, 12.4 dB attenuation at ƒs/4 with a single device, reduced output ringing with constant input in interpolate mode, support for signed and unsigned data formats, rounding to 10 and 8 bit CCIR 601 data formats, masking of serial digital TRS codes in the data stream, and elimination of the non-saturated-type overflow condition. The device can be operated in both TMC2242 compatible modes and in GF9102A enhanced modes.

When used as a decimating post-filter with a double speed oversampling analog-digital converter, the device greatlyreduces the cost and complexity of the associated analog anti-aliasing pre-filter. In a similar fashion, when used as an interpolating pre-filter with a double speed oversampling digitalanalog converter, the GF9102A simplifies the analog reconstruction post-filter. The GF9102A also exceeds the requirements for conversion between 4:2:2 and 4:4:4 signal formats.

For chroma filtering applications, the GF9102A can be operated as a 9 or 21 tap bandpass filter by selecting the appropriate operating mode.

The GF9102A is packaged in a 44 pin PLCC and is pin compatible with the TMC2242. The device operates with a single +5 V supply.