FUNCTIONAL DESCRIPTION (continued)

3.3 - Control Data

Video Amplifier Gain Control (8 bits used)

Address

: 0000

POR value : 0000.0000 ---> 6dB

Gain is expressed from CDSoutput to ADC input

- 0.07dB / LSB step

- Overall range (256 steps) : 17.7dB

Video Gain (dB)

Data

6

0000.0000

6.07

0000.0001

6.14

0000.0010

...

...

7.12

0001.0000

7.19

0001.0001

...

...

23.63

1111.1110

23.7

1111.1111

Black Level Adjustment Control (5 bits used)

Address

: 0001

POR Value : 0001.0000 ---> 16LSB

The adjustment is controlling the black reference

voltage. However, it is preferred to express the

Black level adjustment in terms of the ADC output

code variation (in ADC LSBs, compared to the

nominal default setting) depending on the Black

setting.

Typically, 16 LSBs black level is recommended.

- 1 ADC LSBs / LSB step

- Overall range : 31 ADC LSBs

Black Level

(ADC Ouput Variation)

Data

0 LSBs

XXX0.0000

1 LSBs

XXX0.0001

...

...

30 LSBs

XXX1.1110

31 LSBs

XXX1.1111

Video High Gain Select (1 bit used)

Address

: 0001

POR Value : 0 ---> Nominal gain

This bit controls an extra 12dB gain in the video

path (adding to gain described in previous page).

Video High Gain Select

Data

Nominal Gain

XX0X.XXXX

Extra 12dB Gain

XX1X.XXXX

Video AGCOUT Test Signal ON/OFF (2 bits used)

Address

: 0001

POR Value : 00 ---> High Z pad

A pin is reserved to output the ADC input signal, or

input the ADC input signal for test and evaluation

purpose.

Those bits control the state of the output buffer. To

limit Xtalk and pollutions, the buffer is in High

impedance mode during normal operation.

VAGCOUT PIn State

Data

Normal Operation (High Z Pin)

00XX.XXXX

AGC Output Test

10XX.XXXX

ADC Input Test

11XX.XXXX

Microphone AGC Switch (1 bit used)

Address

: 0010

POR value : 0000.0000 ---> AGC OFF

The switch is controlling the state of the AGC : ON

or OFF.

In OFF mode, the Micro Preamp. is set at a fixed

nominal gain of 52dB.

In ON mode, the AGC is operating in a gain range

[34dB ; 60dB] (see further in this document for

details).

Microphone AGC

Data

OFF

0000.0000

ON

0000.0001

STV0502

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