AN2384 Freescale Semiconductor / Motorola, AN2384 Datasheet - Page 9

• Manufacturer Part Number: AN2384
• Description: Generic Tone Detection Using Teager-Kaiser Energy Operators on the StarCore SC140 Core
• Manufacturer: Freescale Semiconductor / Motorola

4.1 ITU-T Recommendation Q.24
Table 1 shows the AT&T requirements of this recommendation [5].
Freescale Semiconductor
Signal frequencies
Frequency tolerance |
Power levels per frequency
Power level difference (twist) between
high and low frequencies
Signal reception timing
Signal simulation by speech
Interference by echoes
Generic Tone Detection Using Teager-Kaiser Energy Operators on the StarCore SC140 Core, Rev. 1
f |
Parameters
Table 1. AT&T Requirements for ITU-T Recommendation
697
770
852
941
Low group
High group
Operation
Non-operation
Operation
Non-operation
Signal duration:
Operation
Non-operation
Pause duration
Signal interruption
Signaling velocity
1
4
7
*
1209
Figure 4. Telephone Keypad
13
1
5
9
2
5
8
0
1336
10
14
6
2
3
6
9
#
1477
697, 770, 852, 941 Hz
1209, 1336, 1477, 1633 Hz
0 to –25 dBm0
Max. –55 dBm0
DTMF digits must be detected with twists between –8
dB and 4 dB
Min. 40 ms
Max. 23 ms
Min. 40 ms
Max. 10 ms
Min. 93 ms/key
For the codes 0–9, 1 false/3000 calls
For the codes 0–9,*,# 1 false/2000 calls
For the codes 0–9,*,#,A–D, 1 false/1500 calls
Should tolerate echoes delayed up to 20 ms and at
least 10 dB down
1.5%
3.5%
11
15
7
3
A
B
C
D
1633
12
16
8
4
Values
DTMF Detector on StarCore
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