Sony DVP-M35 Operation Manual page 44

The CDE and CDF signals output from the CD optical pickup are converted to the CD
tracking error signal (CDTE @P) at ICOO of (CXA2555Q) the TK-47 board.
The CDTE signal is input to the switch IC (IC452, MC14053) of the MB-78 board.
During CD playback, it is passed through the switch IC (IC452), amplified at IC503,
and input to @P TE of IC506 (DSP CXD8730R).
Like DVD playback, the tracking error signal is gain-adjusted, tracking bias-adjusted,
and tracking auto level-adjusted in the DSP.
The DSP tracking drive signal (T OUT @P) is voltage-amplified, voltage-converted,
and current-amplified by the IC (IC363 BA5981) for tracking driving, and used to
drive the CD pickup tracking coil.
Track jump control during CD search is carried out by IC506 (DSP CXD8730R) as
done during DVD search.
As a result, when performing 1 track jump or N track jump (many track jumps), tracking
pulses are generated, the tracking zero cross timing is detected, tracking brake is
controlled, and the number of track jumps is measured.
* Tracking auto level adjustment.
This function operates only during CD and V-CD playback.When the TE level (traverse
waveform) is small due to the inconsistency of the disc, this level adjustment is
performed to eliminate the inconsistencies. Consequently, like gain adjustment, the
adjustment is performed each time the disc is replaced (tray is opened), to set the
traverse level to 2.0 Vp-p.
After setting the disc and turning ON the focus servo, the peak-to-peak value of the TE
signal (this TE signal is called the traverse signal) is measured by the IC506
The measurement results are read by the IC805 (system control IC) to determine the
gain variable amount. The response (variable amount) is then returned again to IC506
Upon receiving this, IC506 outputs control signal for the tracking auto level adjustment
from @P and @P of the IC506 (DSP:CXD8730R). It is added by IC503 and converted
to the analog voltage (TEATT signal).
The TEATT signal is input to @P of ICOO (CXA2555) of the
TK-47 board, and gain-controlled inside the IC. The variable width is about k3.0 dB.