AK2365A Datasheet, PDF (21/33 Pages) Asahi Kasei Microsystems – FM IF Detector with Narrow Band Filter

[AK2365A]
AGC_TIME[1:0]: AGC response time setting
This register set response time for AGC1 gain and AGC2 gain to change by 1step.
AGC_TIME AGC_TIME
[1]
[0]
AGC response time [ms]
AGC1_STEP=0 setting
AGC1_STEP=1 setting
State A State B
State C
State A
State B
State C
0
0
0.56
8.50
8.50
0.38
4.35
4.35
0
1
0.92
8.79
8.79
0.56
4.50
4.50
1
0
1.64
9.37
9.37
0.93
4.79
4.79
1
1
3.08
10.52
10.52
1.66
5.38
5.38
Note 1: Values above indicate response time during AGC gain changes from maximum to minimum or
from minimum to maximum.
Note 2: The response speed of AGC must be set to AGC_FAST=0, AGC_TIME[1:0]=”11”,
AGC1_STEP=0. ACS (Adjacent Channel Selectivity) performance is optimized by preventing
the periodic operation due to a strong unwanted signal.
State A: AGC1 output level is beyond the upper limit.
State B: AGC1 output level is within the upper limit and AGC2 output level is beyond the upper limit.
State C: AGC2 output level is under the lower limit.
Data
Function
Operation
0
1
Notes
AGC1_ST
EP
AGC1 gain switching range
setting (Note1)
1dB(recommended)
±2dB
CAL
Discriminator circuit calibration
start trigger (Note2)
Invalid
Start
Note 1: The response speed of AGC must be set to AGC_FAST=0, AGC_TIME[1:0]=”11”,
AGC1_STEP=0. ACS (Adjacent Channel Selectivity) performance is optimized by preventing
the periodic operation due to a strong unwanted signal.
Note 2: calibration is performed synchronized with the rising edge of {CAL}. After calibration is
completed, this register is set to “0” automatically. It takes 1.3ms before calibration is
completed.
Refer to “calibration procedure” for further information.
MS1591-E-03
- 21 -
2015/4