GENERAL DESCRIPTION
The SAA4945H, LIMERIC (LIne MEmory noise Reduction IC) is a 2-D recursive noise reduction filter for both luminance and colour difference signals. The noise reduction is automatically adapted to the global noise level in the image. Ten different preferences of noise reduction can be set using a synchronous receiver transmitter bus; SNERT (Synchronous No parity Eight bit Receive Transmit) bus. Alternatively, the noise reduction can be switched off. The LIMERIC is generally placed directly after the ADC in the feature box and works fully in the 1fh (50/60 Hz) domain.

FEATURES
• 2-D adaptive vertically recursive noise reduction
• Noise reduction for Y, U and V signals in 4 : 1 : 1 format
• Single 5 V ±10% power supply
• Communication by means of serial communication protocol 83C654 (SNERT bus)
• Via SNERT bus, 10 different types of noise reduction selectable; the noise reduction function can also be disabled
• Phase relation write enable input/output signal simultaneously switchable over one clock period w.r.t. input/output samples
• 8-bit wide data processing for Y, U and V; in unsigned format (Y signal) and in 2’s complement (U and V signals)
• One fixed line locked clock operation frequency up to 16 MHz (typical)
• Exactly one line delay.