(Solved): 4.4 Telephone Numbers The functions \( d t m f d i a l . m \) and \( d t m f ...

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4.4 Telephone Numbers The functions \( d t m f d i a l . m \) and \( d t m f r u n . m \) can be used to test the entire DTMF system as shown in Fig. 8. You could also use random digits (e.g., ceil \( (15.9 * \) rand \( (1,22)+0.09)) \) in place of \( 1: 16 \) in dtmfdial. For the dtmfrun function to work correctly, all the M-files must be on the MatLAB path. It \( \gg>\mathrm{f}=8000 ; \) ?<-use this sampling rate in all functions \( \gg t k=\left[A^{\prime}, B^{\prime},{ }^{\prime} C^{\prime}, D^{\prime}, D^{\prime} *^{\prime},^{\prime} \#^{\prime}, \prime^{\prime}, \prime^{\prime} 1^{\prime}, 2^{\prime}, \prime^{\prime} 3^{\prime},{ }^{\prime} 4^{\prime},{ }^{\prime} 5^{\prime}, 6^{\prime} 6^{\prime}, 7^{\prime} 7^{\prime}, 8^{\prime}, 9^{\prime}\right] \); \( \gg \mathrm{xx}=\mathrm{dtmfdial}(\mathrm{tk} \), fs ); >soundsc (xx, fs) \( > \) > \( =\ldots \) ?<-use your value of \( \mathrm{L} \) \( \gg \) dtmfrun (xx, L, fs) ans \( = \) \( A_{A B C}{ }^{*} \# 0123456789 \) Figure 8: Testing the DTMF system. is also essential to have short pauses in between the tone pairs so that \( d t m f c u t \) can parse out the individual signal segments. If you are presenting this project in a lab report, demonstrate a working version of your programs by running it on the following phone number: \[ 407 * 89132 \text { \#BADC } \] In addition, make a spectrogram of the signal from \( \mathrm{dtmfdial} \) to illustrate the presence of the dual tones.