ADSP-2101 Implementation

When implementing the DTMF decoder algorithms on the fixed-point ADSP-2101 (16.67 MHz) processor, we sampled touch tones generated by a telephone at 8 KHz and 8 bits. For each algorithm, we compute the estimation errors for each touch tone digit and manually compared it against standards given in Section II. The required programming memory (PM) in words, data memory (DM) in words, and execution time (ET) in s/sample follow. A word is 2 bytes for DM and 3 bytes for PM, and samples arrive every 125 s.

• Goertzel DTMF detector hand-coded in assembly:
  PM = 167, DM = 51, ET = 33.2 s/sample
• NDFET DTMF detector hand-coded in assembly:
  PM = 162, DM = 13, ET = 9.1 s/sample
• MUSIC DTMF detector cross-compiled from C:
  PM = 2071, DM = 1824, ET = 1302 s/sample

• The Goertzel Algorithm
• Normalized Direct Frequency Estimation Technique
• MUSIC Algorithm