BM94801KUT Datasheet, PDF (239/379 Pages) Rohm – Initial Program ROM

BM94801KUT
Datasheet
Figure 110. Focus balance measuring principle chart (Method 1)
When disturbance signal is added to FDOUT, RFRP response differs depending on which is the focal point of the focus, of a
to e points. Herein, RFRP response characteristic is shown in graphs assuming the case of “no phase deviation”. As seen
from the above graph, RFRP phase against disturbance in the case of focal point-a is reverse to that in the case of focal
point-e.
This focus balance measuring function uses FBCO which is the comparative data of RFRP LPF component (=mean value)
and RFRP. Hence, as prescribed it is possible to discriminate deviation direction of the focal point by comparing the time of
FBCO=H under positive disturbance with the time of FBCO=H under negative disturbance.
The disturbance frequency is set to several hundred Hz because the focus sounds at high dB if the frequency comes to
nearly 1kHz.
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TSZ02201-0V2V0E600300-1-2
18.Apr.2014 Rev.003