[ASAHI KASEI]
Recovery Operation
Recovery Time is defined as a reset cycle of Recovery Counter (RC). The cycle can be changed by the combination of MSEL bit,
RWT0 bit, and RWT1 bit. Input signal enters Recovery Zone from other Zones, RC initiates counting. If the signal exits from
Recovery Zone at lease once, RC is reset. When RC's value exceeds Recovery Time, the AK4533 is ready to update IPGA value, and
RC is reset and counts again from "zero". IPGA value is actually updated once just after the signal crosses the ground. Therefore, the
update cycle will change. Note that the update is one time in one Recovery Time and that the update of IPGA value is disabled until
ROC is "zero" even if the signal crosses the ground several times. The AK4533 compares the IPGA value and Recovery Reference
Level at the update timing. If IPGA value is greater than Recovery Reference Level, IPGA value is forced to Recovery Reference
Level.
When the input signal enters Recovery Zone from any other Zones at the first time, the AK4533 waits for one Recover Time without
updating of IPGA. After that, the AK4533 updates IPGA per one Recovery Time at zero-crossing point.
If the signal doesn't cross the ground, the AK4533 forces to update IPGA value after the time of Table 5 passes.
MSEL
“L”
“H”
252Ts
508Ts
8kHz
31.5ms
22.9ms
11.4ms
NA
8kHz
NA
NA
NA
Zero-Cross Timeout
11.025kHz
22.05kHz
44.1kHz
11.025kHz
22.05kHz
44.1kHz
11.5ms
Table 5. Zero-Cross Timeout Table for Recovery Time
Addr = 01h
RSTEP-0:
Recovery GAIN Step
RSTEP0 bit and RSTEP1 bit specify the increment step size of IPGA value at Recovery operation. For example, if the current value of
IPGA is 0x42, and if RSTEP0 and RSTEP1 are "11", IPGA is set to 0x46.
RSTEP1 RSTEP0
GAIN STEP
0.5dB
Default
0
0
1
1
0
1
0
1
1.0dB
1.5dB
2.0dB
Addr = 01h
RWT1-0:
Recovery Time
MSEL
RWT1
RWT0
Recovery Time
8kHz
11.025kHz
22.05kHz
44.1kHz
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
256Ts
512Ts
1024Ts
2048Ts
512Ts
1024Ts
2048Ts
4096Ts
32ms
64ms
128ms
256ms
23ms
46ms
93ms
185ms
11.6ms
23ms
46ms
93ms
-
-
-
Default
-
-
-
-
-
-
-
-
-
-
-
-
-
11.6ms
23ms
46ms
93ms
<Revision 0.9a>
21
July 00
AKM [ ASAHI KASEI MICROSYSTEMS ]
