W925E240 Datasheet, PDF (71/73 Pages) Winbond – 8-BIT CID MICROCONTROLLER

W925E/C240
DTMF Decoder
PARAMETER
Input Sensitivity per tone
SYMBOL MIN.
-29
TYP.
Positive and negative twist accept
7
Frequency Deviation accept
1.5
Frequency Deviation reject
3.5
3rd Tone Tolerance
Noise Tolerance
Dial tone Tolerance
22
Notes :
1. signal consists of all DTMF tones.
2. Tone duration is 40 mS at least, tone pause duration is 40 mS at least.
3. Referenced to the lowest level frequency component in DTMF signal.
4. Referenced to the minimum valid accept level.
MAX.
1
-16
-12
UNITS
dBm
dB
%
%
dB
dB
dB
NOTES
1, 2
1, 2
1, 2
1, 2
1, 2, 3
1, 2, 3
1, 2, 4
DTMF Detection Interface
PARAMETER
CONDITION SYM. MIN. TYP^‡ MAX. UNITS NOTES
DTMF present detect time
DTMF absent detect time
DTMF Detected Duration
DTMF Signal Ignore Time
DTMF Pause Accept Time
Est
t_FP
0.5
t_FA
0.1
DTMFD = 1 t_DD
40
DTMFD = 0
t_DI
DTMFD = 1 t_DPA
20
8
mS
8
mS
mS
20
mS
mS
"‡" Typical figure are at V_DD = 5V and temperature = 25 °C are design aids only, not guaranteed and not subject to production
testing.
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Publication Release Date: July 12, 2005
Revision A10