Updated DAC lowpass filter in documentation

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Niels Moseley 2017-10-26 17:57:09 +02:00
parent 8afd1af0a7
commit 42ad37a956

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@ -2,17 +2,17 @@
* Altera EP3C16F484C6 FPGA * Altera EP3C16F484C6 FPGA
The DAC output is the UART_TX pin. It _really_ needs a 5kHz lowpass filter, otherwise you'll be deafened/greeted by a very loud 10kHz PWM carrier. Try a 330 ohm series resistor, followed by a 100nF capacitor to ground: The DAC output is the UART_TX pin. It _really_ needs a 5kHz lowpass filter, otherwise you'll be deafened/greeted by a very loud 10kHz PWM carrier. Try two sections of a 1K ohm series resistor, followed by a 100nF capacitor to ground:
``` ```
UART_TX pin ----RRRRR---------o OUTPUT UART_TX pin ----RRRRR--------RRRRR---------o OUTPUT
| | |
C C C
C C C
C C C
| | |
GND GND GND
``` ```