cxd2548r Sony Electronics, cxd2548r Datasheet - Page 80

• Manufacturer Part Number: cxd2548r
• Description: Cd Digital Signal Processor With Built-in Digital Servo And Dac
• Manufacturer: Sony Electronics

§4-6. AGCNTL (Auto Gain Control) Function
The AGCNTL function automatically adjusts the filter internal gain in order to obtain the appropriate gain with
the servo loop. AGCNTL not only copes with the sensitivity variation of the actuator and photo diode, etc., but
also obtains the optimal gain for each disc.
The AGCNTL command is sent when each servo is turned on. During AGCNTL operation, if the upper 8 bits of
the serial data are 38 (Hex), the completion of AGCNTL operation can be confirmed through the SENS pin.
(See Timing Chart 4-2 and "Description of SENS Signals".)
Setting D9 and D8 of $38 to 1 set FCS (focus) and TRK (tracking) respectively to AGCNTL operation.
Note) During AGCNTL operation, each servo filter gain must be normal, and the anti-shock circuit (described
Coefficient K13 changes for AGF (focus AGCNTL) and coefficients K23 and K07 change for AGT (tracking
AGCNTL) due to AGCNTL.
These coefficients change from 01 to 7F (Hex), and they must also be set within this range when written
externally.
After AGCNTL operation has completed, these coefficient values can be confirmed by reading them out from
the SENS pin with the serial readout function (described hereafter).
AGCNTL related setting
Note) Converging servo loop gain values can be changed with the FG6 to 0 and TG6 to 0 setting values. In
The following settings can be changed with $35, $36 and $37.
FG6 to FG0; AGF convergence gain setting, effective setting range: 00 to 57 (Hex)
TG6 to TG0; AGT convergence gain setting, effective setting range: 00 to 57 (Hex)
AGS;
AGJ;
AGGF;
AGGT;
AGV1;
AGV2;
AGHS;
AGHT;
XLAT
SENS
(= AGOK)
hereafter) must be disabled.
addition, these setting values must be within the effective setting range. The default settings aim for 0
dB at 1kHz. However, since convergence values vary according to the characteristics of each
constituent element of the servo loop, FG and TG values should be set as necessary.
Self-stop on/off
Convergence completion judgment time
Internally generated sine wave amplitude (AGF)
Internally generated sine wave amplitude (AGT)
AGCNTL sensitivity 1 (during high sensitivity adjustment)
AGCNTL sensitivity 2 (during low sensitivity adjustment)
High sensitivity adjustment on/off
High sensitivity adjustment time
Max. 11.4µs
Timing Chart 4-2.
– 80 –
AGCNTL completion
CXD2548R