Table 2 shows the error percentage in detecting DTMF tones for
the Goertzel algorithm on the ADSP-2101.
Unfortunately, its resolution was not high enough.
For example, for 
with 
KHz sampling rate, resolution in frequency
domain is 
Hz.
This resolution causes an error in meeting standard 2(b).
The DTMF receiver must eliminate the tones outside the specified ranges.
To be more specific, consider a 
Hz tone.
Standard 2(b) enforces the elimination of frequencies outside
Hz for Hz.
However, 
Hz resolution enforces the detection of signals in
Hz to yield 
Hz,
which is impossible with 39 Hz resolution in frequency domain.
Table 2: Goertzel algorithm tests on the ADSP-2101
