AN2384 Freescale Semiconductor / Motorola, AN2384 Datasheet - Page 11

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

Freescale Semiconductor
samples[2*i]:
fsl_dtmf_det (samples, detected_keys, dtmf_data, size_buf);
Generic Tone Detection Using Teager-Kaiser Energy Operators on the StarCore SC140 Core, Rev. 1
Pre-Processing Unit
Frequency Estimation Unit
Digital Validation Unit
samples
AGC Unit
Figure 5. Structure of the TK Algorithm for DTMF Detection
2i
Estimate Frequency Detectors
Determine closest reference
frequency and test for
Estimate Signal Power
frequency tolerance
detected_keys
Do Analysis of
previous_digit
Large Enough?
Re-scale Signal
Is new_digit
previous_digit?
Is Power
L
YES
YES
new_digit
NO
for (i = 0; i < size_buf / 2; i++)
H
NO
Do Analysis of
Digit Processing Unit
Sample Processing Unit
digit
m
new_digit = 0
det
DTMF Detector on StarCore
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