This demo shows the interesting situation that occurs when we have two sinusoidal signals of slightly different frequencies.

This MATLAB demo reconstructs a square, triangle, or
sawtooth waveform, using a given number of Fourier Series coefficients.

This demonstrates the idea of harmonic sinusoids.
Five sinusoids with a common fundamental frequency are
added together, one at a time.

By visualizing the spectrogram of a synthesized chirp and listening to the sound,
we experience the fact that a D-to-C converter cannot create output signals
with frequencies higher than one half of the sampling frequency.

The Continuous-Discrete Sampling Demo (con2dis)
is a program that shows the continuous
and discrete spectra (and signals) during sampling.

**Features:**

- Users can change the input frequency and sampling rate.
- Frequency axis can be labeled in hertz or radians/sec.
- Reconstruction through D/A is also shown.

- Users can choose from a variety of different signals.
- Signals can be dragged around with the mouse with results displayed in real-time.
- Tutorial mode lets students hide convolution result until requested.
- Various plot options enable the tool to be effectively used as a lecture aid in a classroom environment.

A table of DTFT pairs is usually given as a list of formulas for the signal
\(x[n]\) and its DTFT \(X(e^{j \hat\omega})\). These formulas
can be visualized as plots, and this demo focuses on the ability to recognize
signals and transforms in a graphical form.

The Filter Design Demo is a program that designs simple FIR (and IIR) digital filters,
along with tutorial visualizations of the filter design process.

**Features:**

- FIR Design with many different window types
- Numerous plot options: magnitude/phase response, pole-zero diagram, and impulse response
- IIR Design of Butterworth filters
- Parks-McClellan FIR Design showing the iterations of the Remez Exchange method

`specgramdemo`

**Features:**

- Change window length and window type
- Change window overlap
- Change FFT length (zero padding)
- Show 1-D slice of spectrogram
- Plot options: zooming, 30, 40, 50 and 60 dB magnitude ranges, four color maps
- Three signal types: Sum of sinusoids, Linear chirp, Recorded signal, e.g., speech

The Filter Design Demo is a program that designs simple IIR (and FIR) digital filters,
along with tutorial visualizations of the filter design process.

**Features:**

- IIR Design of Butterworth filters
- Numerous plot options: magnitude/phase response, pole-zero diagram, and impulse response
- FIR Design with many different window types
- Parks-McClellan FIR Design showing the iterations of the Remez Exchange method