NSAM266SA Datasheet, PDF (44/52 Pages) National Semiconductor (TI) – NSAM266SA CompactSPEECHTM Digital Speech Processor with Serial Flash Interface

2 0 Software (Continued)
TABLE 2-2 Tunable Parameters (Continued)
Index
Parameter Name
Description
Default
16 TONE GENERATION LEVEL
Controls the energy level at which DTMF and other tones are
6
generated Each unit represents 3 dB The default level is the
reference level
For example if you set this parameter to 4 the energy level is 6 dB
less than the default level The actual output level is the sum of
TONE GENERATION LEVEL and the VOL LEVEL variable
controlled by the VC command The tones are distorted when the level
is set too high The valid range is
0 ^s TONE GENERATION LEVEL a VOL LEVEL ^s 12
17 Reserved
18 TONE TIME COUNT
Controls the duration of a tone before it is reported as a dial tone
700
in 10 ms units The accuracy of the constant is g10 ms
Legal values 0 to 65535
19 TONE ON ENERGY THRESHOLD Minimum energy level at which busy and dial tones are detected as
160
ON (after 700 Hz filtering) If you divide (multiply) the value by 2 you
get a 3 dB decrease (increase) in the threshold
Legal values 0 to 65535
20 TONE OFF ENERGY THRESHOLD Maximum energy level at which busy and dial tones are detected as
110
OFF (after 700 Hz filtering) If you divide (multiply) the value by 2 you
get a 3 dB decrease (increase) in the threshold
Legal values 0 to 65535
21 VCD LEVEL
Controls the energy during playback and external voice synthesis
6
Each unit represents 3 dB The default level is the reference level For
example if you set this parameter to 4 the energy level is 6 dB less
than the default level The actual output level is the sum of VCD
LEVEL and the VOL LEVEL variable controlled by the VC command
Speech is distorted when the level is set too high The valid range is
0 ^s VCD LEVEL a VOL LEVEL ^s 12
22 VOX TOLERANCE TIME
Controls the maximum energy period in 10 ms units that does NOT
3
reset the vox detector
Legal values 0 to 255
23 MIN BUSY DETECT TIME
Minimum time period for busy detection in 10 ms units The accuracy 600
of the constant is g10 ms
Legal values 0 to 65535
24 ECHO DELAY
The near-echo delay in samples The sampling rate is 8000 Hz (i e
4
125 ms per sample)
Legal values 0 to 16
25 Reserved
26 DTMF REV TWIST
Controls the reverse twist level at which CompactSPEECH detects
0
DTMF tones While the normal twist is set at 8 dB the reverse twist
can be either 8 dB (default) or 4 dB (If this parameter is set to 1)
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