AN332
Rev. 0.8
89
Property 0x1100. FM_DEEMPHASIS
Sets the FM Receive de-emphasis to 50 or 75 µs. 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 75 µs.
Available in: All except Si4749
Default: 0x0002
Property 0x1102. FM_CHANNEL_FILTER
Selects bandwidth of channel filter applied at the demodulation stage. Default is automatic which means the device
automatically selects proper channel filter. 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 1.
Available in: Si4706, Si4749, Si4704/05/30/31/34/35/84/85-D50 and later
Default: 0x0001 (Si4706, Si4749, Si4705/31/35/85-D50 and later)
0x0000 (Si4704/30/34/84-D50 and later)
Range: 0–4
Note:
Automatic channel filter setting is not supported in FMRX component 3.0.
Bit
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Name
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DEEMPH[1:0]
Bit
Name
Function
15:2
Reserved
Always write to 0.
1:0
DEEMPH[1:0]
FM De-Emphasis.
10 = 75 µs. Used in USA (default)
01 = 50 µs. Used in Europe, Australia, Japan
00 = Reserved
11 = Reserved
Bit
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Name
FMCHFILT[15:0]
Bit
Name
Function
15:0
FM_CHANNEL_FILTER
0 = Automatically select proper channel filter.
1 = Force wide (110 kHz) channel filter.
2 = Force narrow (84 kHz) channel filter.
3 = Force narrower (60 kHz) channel filter.
4 = Force narrowest (40 kHz) channel filter.