Psk on Lloyd Rochester's Geek Blog

BPSK Receiver Theory

Wed, 17 Feb 2021 00:00:00 +0000

Let’s look at some BPSK Receiver Theory. This is the 3rd post in the PSK Series. We’ll cover the theory before we go into the implementation.

PSK Series

Here is a summary of where we are in the PSK Series.

BPSK Transmit Theory - This post shows graphs and has audio files of what this tool does.
BPSK Implementation
BPSK Receiver Theory - This Post
BPSK Receiver Implementation - Coming Soon
QPSK - Coming Soon

What are we going to receive?

See my previous post on BPSK Transmitter Theory for what the waveform transmitted. For this post we’ll receive and decode this waveform. Effectively, we’re sending symbols that are Root Raised Cosine waveforms multiplied with sinusoids. Below is the encoded text t represented by our alphabet as \( 10100 \). Note, the amplitude of \( ~1000 \), all the “peaks” both positive and negative, and the duration between the peaks. We’ll delve into all these details shortly.

BPSK Transmitter Implementation

Sun, 24 Jan 2021 00:00:00 +0000

BPSK Transmitter Implementation

In the previous post we discussed BPSK Transmit Theory. This post will discuss the implementation of it. This implementation will be in the C programming language and it will also be a command line tool.

PSK Series

I’m doing a series on PSK here is where we are:

BPSK Transmit Theory - This post shows graphs and has audio files of what this tool does.
BPSK Implementation - This Post.
BPSK Receiver Theory - Coming Soon
BPSK Receiver Theory - Coming Soon
QPSK - Coming Soon

Using the Command Line Tool

I like to start out with how the tool is used as it gives insight about the implementation. It’s quite simple, provide text input as a program argument and the tool will output a .wav file with the content. The example below converts the text hello world to the psk31.wav audio file.

BPSK Transmitter Theory

Thu, 14 Jan 2021 00:00:00 +0000

BPSK Transmitter Theory

In this post we’ll get into the theory of Binary Phase Shift Key - BPSK. We’ll then get into the implementation of the transmitter, followed by the same for the receiver. The transmitter will have text as input, for output we will produce an audio .wav file and a CSV file for analysis. I created a bunch of graphs which really illustrate some of the theory.

Transmit Process

Let’s start with the overall transmit process.