Frequency to Frequency Conversion

Ranges

Process

• Mapping speech in range of f_min to f_max Hz to an inaudible range of F_min to F_max
• Amplifying the utterance
• Transmitting the utterance
• Receiving the response from the environment
• Amplifying the response
• Mapping response in range of F_min to F_max back to f_min to f_max.
• Amplifying the mapping

Choice	Limitation	Advantage	Waveform
1) duplicate a section of signal at a higher frequency for a shorter interval	must wait for section to complete before duplication begins	no real time conflict
2) duplicate a section of signal at a higher frequency for the original interval	must wait for section to complete before duplication begins	higher SNR no real time conflict
3) duplicate the frequencies of signal at a higher frequency for the original interval	must wait 1/2 period before duplication begins	higher SNR real time ops