1. © Bob York l Analysis of speech segments. A) Variation of sound pressure level over time for a representative utterance from the TIMIT corpus (the sentence in this example is "She had your dark suit in greasy wash water all year"). B) Blowup of a 0.1 second segment extracted from the utterance (in this example the vowel sound in "dark"). C) The spectrum of the extracted segment in (B), generated by application of a fast Fourier transform.

2. © Bob York Modulation Signal PWM T

3. © Bob York Baseband signal spectrum Carrier “sidebands” representing baseband signal

4. © Bob York Full Schematics for Modulator LM393N

5. © Bob York Partial Schematics LM393N

6. © Bob York Partial Schematics LM393N

7. © Bob York IR signal emitter flat I photo