Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Funny Voice Coder
Document related concepts
Power inverter wikipedia , lookup
Variable-frequency drive wikipedia , lookup
Current source wikipedia , lookup
Ringing artifacts wikipedia , lookup
Stray voltage wikipedia , lookup
Immunity-aware programming wikipedia , lookup
Phone connector (audio) wikipedia , lookup
Alternating current wikipedia , lookup
Voltage optimisation wikipedia , lookup
Mains electricity wikipedia , lookup
Resistive opto-isolator wikipedia , lookup
Public address system wikipedia , lookup
Field-programmable gate array wikipedia , lookup
Power electronics wikipedia , lookup
Voltage regulator wikipedia , lookup
Schmitt trigger wikipedia , lookup
Buck converter wikipedia , lookup
Switched-mode power supply wikipedia , lookup
Current mirror wikipedia , lookup
Transcript
Funny Voice Coder 03-130435 Shotaro TSUJI January 23, 2014 What is This? A simple vocodar. It has a LPF and one effect. ▶ LPF (cutoff 200Hz) ▶ LPF (cutoff 4kHz) ▶ funny voice effect It consists of Microphone (Input), DSP (FPGA) and Speaker-Lineout (Output). Components ▶ Microphone C9767 ▶ OpAmp NJM2732D (JRC) ▶ FPGA-board DE0-nano (Altera, Terasic) ▶ FPGA Cyclone IV E ▶ ADC ADC128S002 (on-board) ▶ DAC MCP4922 A Problem ADC can quantize voltage between 0V and 3.3V only. But microphone output voltage is around 1mV on direct current. So I should cut DC and amplify its output appropriately. Solution The following is Mic-PreAmp circuit Vcc 4700p 51k 1.5k 2k 1k 100u + 51k 4700p 51k GND 51k 47u 220p 22k 1k + Vout Effect Implementation LPF is implemented as IIR filter. This is designed from simple 1-degree analog LPF with the impulse invariance. Funny voice effect is implemented merely by multiplying 400Hz sin-wave to the original voice. This operation results frequency shift on the voice. These are very simple and able to be done in time domain.
