5.16 DTMF Generation Mode
Introduction
Dual Tone Multi Frequency generation mode generates the
A start delay can be specified for each digit. The duration of each digit can also be specified. These two parameters make it possible to test the performance DTMF detection systems. By sending a string of digits to dial to the
NOTE: The 4071 can generate a single DTMF digit on a repetitive basis by switching to Dualtone Generation mode and setting each Dualtone frequency to that of the desired DTMF digit. The ON and OFF times can then be set to repetitively generate the digit for the desired duration and repetition rate. Refer to the chapter on Dualtone Generation mode for more information.
Background
A DTMF dialing tone consists of two sinusoids of different frequencies, which are added together to form the output waveform. These frequencies were chosen so that they are not harmonically related. The table below lists each dialing digit and its associated Dualtone frequencies:
DTMF 0: 941 Hz and 1336 Hz
DTMF 1: 697 Hz and 1209 Hz
DTMF 2: 697 Hz and 1336 Hz
DTMF 3: 697 Hz and 1477 Hz
DTMF 4: 770 Hz and 1209 Hz
DTMF 5: 770 Hz and 1336 Hz
DTMF 6: 770 Hz and 1477 Hz
DTMF 7: 852 Hz and 1209 Hz
DTMF 8: 852 Hz and 1336 Hz
DTMF 9: 852 Hz and 1477 Hz
DTMF ∗: 941 Hz and 1209 Hz
DTMF #: 941 Hz and 1477 Hz
DTMF A: 697 Hz and 1633 Hz
DTMF B: 770 Hz and 1633 Hz
DTMF C: 852 Hz and 1633 Hz
DTMF D: 941 Hz and 1633 Hz
DTMF Generation Mode Parameters
The DTMF Generation mode has the following front panel display:
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| Delay: | 0 mS | Level: |
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Figure
1. Generated DTMF Digit
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The last DTMF digit that was generated is displayed in this field. To generate a DTMF digit, the cursor must be either in this field or the OFF position. If the cursor is in any other field (i.e. Delay or Duration fields) then the keypad functions to enter those parameters.
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BK Precision 4071 User Manual Rev.2.2
