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greenjacketgirl / SDR_Receiver

This project is an attempt at designing and building a Software Defined Radio receiver that has the capabilities of listening to frequencies ranging from 500kHz to 50MHz utlizing the board designed, a sound card, and Quisk coupled with arduino code.
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Incorrect Bandpass Filter Selection #6

Closed greenjacketgirl closed 4 years ago

greenjacketgirl commented 4 years ago

Background

An arduino nano is flashed with a test program that can be edited to tell the D3 and D4 pins of the arduino to set the select lines of the FST3253 multiplexer to choose the specified bandpass filter. Where D3 -> s0 and D4 -> s1

Description of Issue

I programmed the arduino to set the bandpass filter to the second one (3-5MHz) which corresponds to the select lines s0 = HIGH and s1 = LOW. Therefore, in the arduino test code, I set D4 = LOW and D3 = HIGH. But when I used the oscilloscope to look at the bandpass filters, I had a signal passing through the first filter instead of the second. The first filter corresponding to s0 = D3 = LOW and s1 = D4 = LOW.

I have be unable to figure out why this is. I double checked the code (see attached image) and I double checked the truth table in the datasheet for the multiplexer (also attached as an image). After some time working on it, I decided to move on and figure it out later, as I am still able to test the rest of the circuit, just using the 1st bandpass filter and not the second.

 Screenshot 2020-06-05 08 34 56 Screenshot 2020-06-05 08 36 38

greenjacketgirl commented 4 years ago

update

Since I got the rest of the board working using just the first bandpass filter. I decided to move onto using quisk (_quiskconf.py and _openradioquisk.ino) for programming the arduino for setting the local oscillator frequency and the selecting the bandpass filter. Therefore I am disregarding this issue and replacing it with working on getting the bandpass filter selection working with the new arduino and python program