AK2401 Datasheet, PDF (64/103 Pages) Asahi Kasei Microsystems – Direct Conversion Transceiver

[AK2401]
AGCOFF bit
AGC Status
Wait
Power Detect
Wait
Power Detect
Wait
Power Detect
PGA Gain
Initial Value
Wait
: Period set by AGCTRW bit
Power Detect: Period AGCTIM bit
PGA Gain Initial Value: PGAGAIN_I, PGAGAIN_Q bits Setting
Figure 37. AGC Operation Timing Chart
13.8.9. AGC_KEEP Function
The AK2401 has a gain keep function. This function is controlled by the AGC_KEEP pin or AGC_KEEPR
bits <Address 0x1F>. AGC_KEEP_SEL bits <Address 0x1F> switch register or pin controlling. The AGC
KEEP function is ON by setting AGC_KEEP bit to “1” or the AGC_KEEP pin to “H”. The operation mode
for this function can be set by AGCKP_MODE[1:0] bits <Address 0x21>. The details of
AGCKP_MODE[1:0] bits settings are shown below.
 AGCKP_MODE[1:0] bit= “00”
When the AGC KEEP function is OFF, a real-time PGA gain change is executed by detecting / calculating
the signal power by AGC operation. When the AGC KEEP function is turned ON, the PGA gain value at
the time will be kept. AGC operation is stopped and power detection/calculation is not executed while
AGC_KEEP bit is “1” (AGC_KEEP pin is “H”). Time counters of AGCTIM bits and AGCTRW bits are also
cleared in this time. AGC operation is resumed when the AGC KEEP function is turned OFF with the PGA
gain that is kept by AGC KEEP function as initial value. Figure 38 is a timing chart of this mode.
AGC_KEEP pin
AGC_KEEPR bit
AGC Status
PGA Gain
W PW PW
W PW PW
W PW P
W : Wait
P : Power Detect
Figure 38. AGC Operation when AGCKP_MODE[1:0] bits= “00”
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