Which IC1 (SAA4977H) for the control circuit, with the implementation of bus commands, control of other circuits and coordination
The role of the work, but also with Y, U, V signal before the progressive scan A / D conversion and subsequent D / A conversion
IC2 (SAA4956TJ) is a 2.9MB memory with noise cancellation, IC4 (SAA4955TJ) is
2.9MB digital high-capacity field signal memory, which are responsible for storing a field of image signals, and IC1
Read / write command under the control of the IC6 to write or read image signal.
IC6 (SAA4991WP) as the core of progressive scan and motion compensation integrated circuits.
From the image demodulation IC TDA9321H 49 feet analog output brightness signal sent to IC1's 26 feet, and 51 feet from the TDA9321H output U, V signal sent to IC1's 28 feet, 30 feet, as 50Hz analog video signal input.
Line, field sync pulse by the IC1 large screen color TV new circuit technology, high frequency multiplication progressive scan / quality improvement circuit 22 feet, 20 feet were introduced as a 50Hz field frequency line frequency input signal.
These signals in the IC1 internal A / D conversion and progressive scan conversion, the converted 8-bit digital Y signal output from 38 feet to 45 feet IC1; 4 U, V signal from IC1's 34 feet ~ 37 feet output, are sent to the field memory IC2.
The IC1 not only performs A / D conversion on the 50Hz analog Y, U, V signals from the image demodulation circuit, but also performs progressive scan conversion of the transmitted line and field sync pulses to obtain 100Hz interlaced scanning or 50Hz progressive sweep
Describe the desired line, field sync pulse.
Multiplication processing circuit SAA4991WP (IC6) not only for digital image signal line-by-line conversion, but also to carry out motion simulation signal compensation.
After its conversion 100Hz interlaced scanning or 50Hz progressive scan digital image signal to 4: 1: 1 format and returned to IC1, in IC1 after anti-format processing and discrete cosine transform to send three 10bit D / A converter ,
Thus reduced to analog Y, U, V signals were output.