[thumbnail=float-right]http://engineerjs.com/almcsi.png[/thumbnail]may I advertise a little bit a free online tool? Two of my colleagues were involved in this project.
This is a free computing environment for scientific and engineering calculations.
It is under heavy development. Just for example there is a FIR filter designer script too. (Remez algorithm) It can plot curves, etc..
Take a look there: EngineerJS.com
This is an ECG lowpass decimator for fsample=2kHz; fcut=4-500Hz :
Code: Select all
import signals.filters.tfilter-1;
// Lowpass
filter=remezFIRFilter(0, 2 kHz, [
{
gain: 1, // passband
ripple: 5dB,
start: 0Hz,
stop: 400Hz
},
{
gain: 0, // stopband
atten: -40dB,
start: 500Hz,
stop: 1000Hz
}
]);
filter.plotAmplitude()
filter.num