Hardware/Parallelport/heb microphone
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The highpass has a cutoff frequency of ... Hz. | The highpass has a cutoff frequency of ... Hz. | ||
The amplifier has a gain of xxx. | The amplifier has a gain of xxx. | ||
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| + | The trigger is a [https://en.wikipedia.org/wiki/Schmitt_trigger Schmitt trigger]. | ||
| + | When there is no signal, the trigger output can be as well low or high. | ||
[[Category:Hardware]] [[Category:Parallelport]] [[Category:HEB]] | [[Category:Hardware]] [[Category:Parallelport]] [[Category:HEB]] | ||
Revision as of 11:59, 18 May 2018
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The board was designed for the SEm VHDL FSM lab.
It has a beeper which can emit a Morse code signal and a microphone for receiving it.
| Version | Photo | Schematics | Stock |
|---|---|---|---|
| V1.1 |  |
HEB-microphone Schematic PDF | 10 fully mounted |
Beeper
The beeper is driven directly by a digital I/O line.
Microphone
The microphone's output is amplified and connected to an ADC. The amplified signal is also triggered in order to deliver a simple digital input to the FPGA.
Setup
The microphone's output is quite small. It is first fed to a fixed amplifier through a passive RC highpass. The highpass has a cutoff frequency of ... Hz. The amplifier has a gain of xxx.
The trigger is a Schmitt trigger. When there is no signal, the trigger output can be as well low or high.
