u/ispeakdsp

VectorSpin by The DSP Coach has been updated to embed saved settings in the URL (thank you Jason Sachs), and the ability to view individual phasors in the IQ plot by clicking on the related impulse in the time or frequency domain magnitude and phase plots.

Create your own here: vectorspin.dsp-coach.com

Other related independently created Pi spinning phasor creations: https://youtu.be/P4cjLFpqU9c?si=_Y7U713xydxaE0bk and https://youtu.be/r6sGWTCMz2k

The VectorSpin program by dsp-coach.com is now live for interactive use. Here we see it demonstrating the frequency response for a 5 tap unity gain FIR filter (moving average filter). The frequency response is plotted as a magnitude and phase plot (showing how it is a low pass filter), as well as the same plot on a complex plane, showing the concept of spinning phasors:

The transfer function for this filter is H(z) = 1 + z⁻¹ + z⁻² + z⁻³ + z⁻⁴.

The frequency response (when z is restricted to the unit circle) for each of these components are phasors in the frequency domain (we see this with the IQ plot):

1 is a phasor in the frequency domain with magnitude 1 and angle zero (it does not rotate).

z⁻¹ is a phasor in the frequency domain rotating clockwise once.

z⁻² rotates twice, etc.

Combining all 5 phasors is the result we see above, here scaled by dividing by 5.

Fast link to the tool so you can try your own samples and many other options:

https://vectorspin.dsp-coach.com/vector_spin.html

More detailed explanations:

https://www.dsp-coach.com/reference

We're developing a source-available DSP learning platform called "RadioSonic" to be released this summer. To see more details of RadioSonic in action, see the recording of my presentation "RF in Slow Motion" here: https://sigprolabs.com .

This talk was originally presented as the opening presentation at the 2026 New England Workshop on Software Defined Radio (NEWSDR) and later as an invited talk for the IEEE Philadelphia Section (the linked recording).

We're also developing fun DSP courses based on this platform, with the first course "Digital Filters" to be announced later this summer. If you want to be on the notify list, email info@sigprolabs.com and put PILOT in the subject or body.

We're developing a source-available DSP learning platform called "RadioSonic" to be released this summer. To see more details of RadioSonic in action, see the recording of my presentation "RF in Slow Motion" here: https://sigprolabs.com .

This talk was originally presented as the opening presentation at the 2026 New England Workshop on Software Defined Radio (NEWSDR) and later as an invited talk for the IEEE Philadelphia Section (the linked recording).

We're also developing fun DSP courses based on this platform, with the first course "Digital Filters" to be announced later this summer. If you want to be on the notify list, email info@sigprolabs.com and put PILOT in the subject or body.