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MSP3440G 参数 Datasheet PDF下载

MSP3440G图片预览
型号: MSP3440G
PDF下载: 下载PDF文件 查看货源
内容描述: 多标准音频处理器系列 [Multistandard Sound Processor Family]
分类和应用:
文件页数/大小: 106 页 / 1906 K
品牌: MICRONAS [ MICRONAS ]
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DATA SHEET  
MSP 34x0G  
6.3. Manual/Compatibility Mode:  
6.3.1.1. Function in Automatic Sound Select Mode  
Description of Demodulator Write Registers  
The Automatic Sound Select feature (MODUS[0]=1)  
includes the procedure mentioned above. By default, the  
internal ERROR_RATE threshold is set to 700dec. i.e.:  
6.3.1. Automatic Switching between NICAM and  
Analog Sound  
– NICAM analog Sound if ERROR_RATE > 700  
– analog Sound NICAM if ERROR_RATE < 700/2  
In case of bad NICAM reception or loss of the  
NICAM-carrier, the MSP 34x0G offers an Automatic  
Switching (fall back) to the analog sound (FM/AM-  
mono), without the necessity for the controller of reading  
and evaluating any parameters. If a proper NICAM sig-  
nal returns, switching back to this source is performed  
automatically as well. The feature evaluates the NICAM  
ERROR_RATE and switches, if necessary, all output  
channels which are assigned to the NICAM-source, to  
the analog source, and vice versa.  
The ERROR_RATE value of 700 corresponds to a  
BER of approximately 5.46*10-3 /s.  
Individual configuration of the threshold can be done  
using Table 6–5. However, the internal setting used by  
the standard selection is recommended.  
The optimum NICAM sound can be assigned to the  
MSP output channels by selecting one of the “Stereo  
or A/B”, “Stereo or A”, or “Stereo or B” source chan-  
nels  
An appropriate hysteresis algorithm avoids oscillating  
effects (see Fig. 6–1). STATUS[9] and C_AD_BITS[11]  
(Address: 0023hex) provide information about the actual  
NICAM-FM/AM-status.  
6.3.1.2. Function in Manual Mode  
Selected Sound  
NICAM  
If the manual mode (MODUS[0]=0) is required, the  
activation and configuration of the Automatic Switching  
feature has to be done as described in Table 6–6. Note  
that the channel matrix of the corresponding out-  
put-channels must be set according to the  
NICAM-mode and need not to be changed in the FM/  
AM-fallback case.  
analog  
sound  
ERROR_RATE  
threshold/2  
threshold  
Example:  
Fig. 6–1: Hysteresis for Automatic Switching  
Required threshold = 500: bits[10:1] = 00 1111 1010  
Table 6–5: Coding of Automatic NICAM/Analog Sound Switching;  
Automatic Sound Select is on (MODUS[0] = 1)  
Mode  
Description  
AUTO_FM [11:0]  
ERROR_RATE- Source Select:  
Threshold/dec  
Addr. = 00 21  
Input at NICAM Path1)  
hex  
1
Automatic Switching with  
internal threshold  
bit[11:0] = 0  
700  
NICAM or FM/AM,  
depending on  
Default  
ERROR_RATE  
2
Automatic Switching with  
external threshold  
(Customizing of Automatic  
Sound Select)  
bit[11]  
bit[10:1] = 25...1000  
= threshold/2  
= 0  
set by customer;  
recommended  
range: 50...2000  
bit[0]  
= 1  
3
Forced Analog Mono  
bit[11]  
bit[10:1] = ignored  
bit[0] = 1  
= 1  
always FM/AM  
1)  
The NICAM path may be assigned to “Stereo or A/B”, “Stereo or A”, or “Stereo or B” source channels  
(see Table 2–2 on page 12).  
Micronas  
May 27, 2003; 6251-476-1DS  
89  
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