DATA SHEET

DEVICE DESCRIPTION

The GF9102A is a linear phase FIR digital filter that is usable

in a variety of video signal processing applications. The device

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 greatly

reduces 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 digital-

analog 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.

FEATURES

• improved performance over TMC2242 in applications

not requiring 1:1 low pass filtering

• low power (60mA typical at ƒ = 20MHz)

• 40 MHz maximum clock rate

• single device exceeds CCIR 601 lowpass filter

requirements

• true unity gain (0.0 dB) at DC

• reduced output ringing with constant input in

interpolation mode

• built-in TRS code protection

• 12 bit inputs and 16 bit outputs in 2's complement

signed or unsigned formats

• user-selectable 8 to 16 bit output rounding

• can also be operated as a 9 or 21 tap chroma

bandpass filter under user control

• single +5 V power supply

• three state outputs

APPLICATIONS

• CCIR 601-compliant oversampling video A/D and

D/A conversion

• 2:1 interpolation and decimation

• 4:2:2 to 4:4:4 format conversion

• Chroma bandpass filtering

Multi

GEN

Decimating/Interpolating Digital Filter

INPUT

PROCESSING

UNIT

OUTPUT FORMAT

TIMING CONTROLS

CLK

DEC

SYNC

DATA IN

SI11..0

BPF1

OUTPUT

PROCESSING

UNIT

INT

TCO

BPF2

53 TAP LPF

M

U

X

SO3..0

RND2..0

DATA OUT

SO15..0

OE

FUNCTIONAL BLOCK DIAGRAM

Revision Date: February 1996

ORDERING INFORMATION

Part Number

Package Type

Temperature Range

GF9102ACPM

44 Pin PLCC

0

° to 70° C

GF9102ACTM

44 Pin PLCC Tape

0

° to 70° C

GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 tel. (905) 632-2996 fax: (905) 632-5946

Gennum Japan Corporation: A-302 Miyamae Village, 2-10-42 Miyamae, Suginami-ku, Tokyo 168, Japan

tel. (03) 3334-7700

fax (03) 3247-8839

Document No. 521 - 26 - 02