Silicon Laboratories Si47 Series Programming Manual page 105

Recommended Block Error Threshold options:
2,2,2,2 = No group stored if any errors are uncorrected.
3,3,3,3 = Group stored regardless of errors.
0,0,0,0 = No group stored containing corrected or uncorrected errors.
3,2,3,3 = Group stored with corrected errors on B, regardless of errors on A, C, or D.
Property 0x1503. FM_RDS_CONFIDENCE
Selects the confidence level requirement for each RDS block. A higher confidence requirement will result in fewer
decoder errors (% of blocks with BLE<3 that contains incorrect information) but more block errors (% of blocks with
BLE=3). The CTS bit (and optional interrupt) is set when it is safe to send the next command. This property may
only be set or read when in powerup mode. The default is 0x1111.
Available in: Si4706-C30 and later, Si474x, Si4704/05/30/31/34/35/84/85-D50 and later
Default: 0x1111
Bit D15 D14 D13
X X X
Name
Bit Name
11:8 CONFIDENCEB
7:4 CONFIDENCEC
3:0 CONFIDENCED
Property 0x1700. FM_AGC_ATTACK_RATE
Sets the AGC attack rate. Larger values provide slower attack and smaller values provide faster attack. The CTS
bit (and optional interrupt) is set when it is safe to send the next command. This property may only be set or read
when in powerup mode. The default is 4 (approximately 1500 dB/s).
Nominal "6000" is based on 50  source impedance and will vary with source impedance. In most systems, an
exact value is not important. However, to calculate for a different source impedance, perform the following steps:
1. Drive antenna input with desired source impedance (via antenna or antenna dummy).
2. Increase RF level until AGC index changes from 0 to 1. Record last RF level with index equal 0.
3. Increase RF level until AGC index reaches 20. Record RF level with index equal 20.
4. Replace "6000" in rate equation with "(RF20 – RF0)/0.00667".
Available in: Si4740/41/42/43/44/45/49
Default: 0x0004
Step: 4
Range: 4–248
D12 D11 D10 D9
X CONFIDENCEB[3:0]
Selects decoder error rate threshold for Block B.
Selects decoder error rate threshold for Block C.
Selects decoder error rate threshold for Block D.
AGC Attack Rate (dB/s)
Rev. 0.8
D8 D7 D6 D5 D4
CONFIDENCEC[3:0]
Function
6000
= -------------------------------------- -
 
ATTACK 7:0
AN332
D3 D2 D1 D0
CONFIDENCED[3:0]
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