AK2400 Datasheet, PDF (24/52 Pages) Asahi Kasei Microsystems – High integrated receiver for PMR-LMR

[AK2400]
Address 0x06
OFST[17:0] : Set the adjustable frequency offset in 2’s complementary representation.
OFFSET register must be written at the speed calculated by “1/3.5*RF Frequency/(INT+7)”. If
the writing speed is faster than this, the setting isn’t valid.
This register is offset from carrier frequency.
After this register is accessed, NUM[17:0] and INT[14:0] are recalculated and their
recalculated data are used in delta-sigma and N-divider. When this register is not used, this
register must be written 00000 (hexadecimal).
When OFFSET register is used, set DITH=0(OFF).
Address 0x07
AGC_KEEP : The function of AGC1/2 gain keeping
When the AGC function is active, the gain setting of AGC1/2 is kept during {AGC_KEEP}=1.
On the other hand, the gain setting of AGC1/2 is changed by IFIP signal during
{AGC_KEEP}=0.
0 : the gain setting of AGC1/2 is changed by IFIP signal. (default)
1 : the gain setting of AGC1/2 is kept.
AGCLVL_H[2:0]: Setting the upper limit of AGC threshold level.
AGCLVL_H
[2]
AGCLVL_H
[1]
AGCLVL_H
[0]
upper limit
0
0
0
-5dB
0
0
1
-4dB
0
1
0
-3dB
0
1
1
-2dB
1
0
0
-1dB
1
0
1
0dB (default)
1
1
0
1dB
1
1
1
2dB
AGCLVL_L[2:0]: Setting the lower limit of AGC threshold level.
AGCLVL_L
[2]
AGCLVL_L
[1]
AGCLVL_L
[0]
lower limit
0
0
0
-8dB
0
0
1
-6dB
0
1
0
-4dB
0
1
1
-2dB
1
0
0
0dB (default)
1
0
1
1dB
1
1
0
2dB
1
1
1
3dB
Note 1) When the AGC1/2 output level is bigger than the upper limit value, AGC1/2 gain is
decreased. When the AGC1/2 output level is smaller than the lower limit value, AGC1/2
gain is increased. The upper/lower limit level is tunable based on default setting limit
value.
Note 2) When AGC function is active ({AGC_OFF}=0), AGC1/2 works as Note1..
CAL : Discriminator circuit calibration start trigger Discriminator
0 : Invalid
1 : Start
Note ) : Calibration is performed synchronized with the rising edge of {CAL}.
After calibration completed, this register is set to “0” automatically. It takes 1.3ms
before calibration is completed. Refer to “calibration procedure” for further information.
014008989-E-01
24
2015/4