BasicDSP v2.0 24-2-2017

Documentation

Introduction

BasicDSP is an educational program that lets users experiment with simple Digital Signal Processing (DSP) algorithms. It compiles on Windows, OSX and Linux with QtCreator and the Qt framework.

For every input sample, a script is run to calculate an output sample. Input samples can come from a sound card or several built-in sources, including stereo .wav files. It features an oscilloscope and a spectrum analyzer

BasicDSP can be used to explore DSP algorithms, such as:

• Digital filters
• Digital PLL design
• Spectral analysis
• Non-linear functions (waveshapers, frequency mixers etc)
• Software-defined radio algorithms
• Sigma-delta noise shapers

Script commands

• mod1(x) - returns the remainer of a division by one.
• sin1(x) - returns sin(2pix)
• cos1(x) - returns cos(2pix)
• sin(x) - returns sin(x), where x is in radians
• cos(x) - returns cos(x), where x is in radians
• tan(x) - returns the tangent of x, where x is in radians
• tanh(x) - returns the hyperbolic tangent of x, where x is in radians
• limit(x) - clamps x to be within -1..1
• round(x) - rounds x to the nearest integer
• sqrt(x) - returns the square root of x
• pow(x,y) - returns x^y
• abs(x) - returns the absolute value of x
• atan2(y,x) - returns the arctangent of (y/x)
• sign(x) - returns 1 if x>=0 and -1 if x < 0.
• noise() - returns white noise with amplitude between -1 and 1.
• trunc(x) - rounds x toward zero, returning the nearest integral value that is not larger in magnitude than x.
• ceil(x) - rounds x upward, returning the smallest integral value that is not less than x.
• floor(x) - rounds x downward, returning the largest integral value that is not greater than x.
• choose(x,v1,v2) - returns v1 if x>=0 or v2 if x < 0

Variables

• inl - left input channel
• inr - right input channel
• in - (left+right)/2
• outl - left output channel of sound card
• outr - right output channel of sound card
• out - writes to both left and right output channels of sound card
• samplerate - a read-only variable that contains the sample rate in Hz

Build instructions

• Download and install QtCreator and Qt 5.5 (or a higher 5.x release).
• Start QtCreator.
• Load the basicdsp.pro project file.
• Configure the Qt toolchain when asked, i.e. where to build the binary.
• Change to a Release build if desired (option in lower left-hand corner).
• Choose Build -> Build All from the main menu.
• If all goes well, you should have a working binary.
• Report bugs to @TRC_WM on twitter or send mail to: n.a.moseley email_at_sign gmail.com