PEDL86V7668-01
OKI Semiconductor
ML86V7668
FUNCTIONAL DESCRIPTION
This section explains the basic functions of the IC in terms of the blocks shown in the block diagram.
Refer to the User's manual for detailed explanations of the internal registers and any functions that are not covered
in this data sheet.
Analog Section
The analog section inputs video signals. The analog section uses the video signal channel selector, AMP and 10-bit
ADC to select the desired channel from among several video signals and convert the input to digital video data.
Analog input selector
The analog input selector is compatible with composite signals and S-video signals. The maximum number of
input connections is 4 channels of composite signals or 3 channels of S-video signals + 1 channels of composite
signals. The selection of these input connections can be changed by external pins or by register controls using
the I2C-bus.
# Related register: $68/ADC1[2:0]
Clamp function
The clamp fixes the video input signal in the ADC input range. Clamping is performed by sync chip clamp.
AMP/analog AGC function
This function converts video input signals to the optimum level for the ADC using the analog AMP of the AGC
function. The AGC function has an output level adjust function in the luminance block of the digital section in
addition to the AMP input level adjust function. Manual setting of the AMP gain is also possible.
# Related register: $69/ADC2
A/D converter
This 10-bit A/D converter (ADC) converts analog video signals to digital video data. There are 2 channels
built into the ADC. Sampling is performed at the pixel frequency or double-speed.
# Related registers: $68/ADC1, $69/ADC2, $6A/ADC3
Digital Section
The digital section separates the video data digitized by the ADC into Y and C data, converts these data to
various data formats and outputs them. The digital section also performs output level adjustment, image quality
adjustment and various corrections.
Decimation filter
Since internal processing is performed at a single speed, this filter is needed to reduce the data that has been
doubled by one-half. Using the decimation filter after double-speed sampling reduces high-frequency noise .
# Related register: $08/FIFOBC[7]
2-dimensional Y/C Separation Block
This block separates composite data into Y (luminance) data and C (chrominance) data. For S pin input, Y/C
separation circuit is bypassed. The Y/C separation function works only for lines which are active as image data
and is bypassed for composite signals in the V blanking period.
2-Dimensional Y/C Separation Function
With the Y/C separation filter, composite data is separated into Y (luminance) data and C (chrominance) data.
There are various Y/C separation filters available, which can be selected in an internal register.
Y/C separation of the SECAM signal is performed by the trap filter.
# Related register: $10/YC1, $11/YC2
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