Overview

The LA7425 is a single-chip video signal processing IC for use in VHS format VCR products. The number of required adjustments has been reduced to a single adjustment by IC chip internal trimming. The incorporation of a playback equalizer and other circuits on chip provides a significant reduction in external components and thus significantly reduces the cost of manufacturing the signal processing printed circuit board. This product can also support simplified S-VHS playback, which is becoming a standard feature in VCR products in the Japanese market.

Features

• Only one adjustment point (comb filter phase adjustment) (The AGC, carrier, deviation and PB-Y level are adjustment free.) (If an LA7411/16 is used as the head amplifier, the Y/C record current will also be adjustment free.)

• Simplified S-VHS playback support

— Built-in S-VHS discrimination circuit

— Built-in equalizer switch

— Automatic demodulator gain switching

— Internal automatic de-emphasis characteristics switching

• Only a minimal number of external components required (85 components: This corresponds to a 38 reduction over previous Sanyo products ... CNR and SQPB not handled, and REC EQ not included.) Components newly incorporated on chip:

— Playback equalizer (include chroma trap), limiter balance filter, capacitor and resistor for detail enhancer, record chroma 7.8 MHz trap, playback chroma LPF, ACC filter

• High performance/multifunctionality

Linear phase type picture controller Double high-pass noise canceller, high-speed AFC, DCC New built-in functions

— FM AGC, synchronization detection circuit, linear control circuit for high-pass noise canceller, playback mode Y/C separator output, chroma noise canceller

• Single CCD system

The LA7425 supports the following functions with the addition of only a single CCD (1H delay) device: comb filter, YNR, DOC and chroma crosstalk cancellation.

Thus the cost of external components is lowered.

• Full HQ support (YNR, CNR, detail enhancer and WCL up)