-
Fourier transforms
Explore the relationship of signals in the time and frequency domain. Adjust time parameters and see how the spectrum changes! Take a look at selected Fourier transform pairs of waveforms and pulses.
-
Signal-to-noise ratio demonstrator
How does music or speech sound in different signal qualities? Recognize that it's the signal-to-noise ratio (SNR) that matters. Observe the visual and auditive impact of added noise.
-
Peak-to-average power ratio of signals
The Peak-to-average power ratio (PAPR) of a signal is the peak power divided by the average power.
-
LTI system - RC low-pass filter
Measure amplitude and phase of the output sine wave signal using an oscilloscope. Compare the results with the transfer function representing the linear time-invariant (LTI) system.
-
LTI systems
See the impulse response and transfer function of various LTI systems. Measure amplitude and phase responses. Why do these filters have a linear phase?
-
Spectra of FM signals
Frequency modulation signal spectra show sidebands for sinewave modulation. In this experiment we take a look how they change with the modulating signal amplitude.
-
FM transmitter
Produce a frequency modulated transmission signal. Select music, speech, microphone or take your own audio file. Demodulate the signal using the FM receiver or let a USRP SDR transmit...
-
FM receiver
Demodulate the FM transmission signal. Listen to the received music or speech. Check if you modulated the audio signal properly and the frequency deviation is adjusted properly...
-
Amplitude modulation
The invention of amplitude modulation made radio broadcasting possible. The message signal varies the carrier amplitude. Analyze an AM-signal in time and frequency domain and...
-
AM transmission - envelope detector
An easy way to recover the messsage signal of an AM-modulated signal is the envelope demodulator. In its simplest form the envelope...
-
AM transmission - synchronous detector
In AM transmissions without carrier a simple envelope detection is not possible. A more complex synchronous or coherent detection is required...
-
Uniform quantization
How does music or speech sound for different quantization resolutions? Explore how the quantization error degenerates the audio signal and each bit per sample improves the Signal-to-quantization-noise ratio by 6 dB.
-
Non-uniform quantization
Explore how the use of compressors and expanders (companding) improves the signal quality compared to uniform quantization - especially for quiet voice. Logarithmic Laws - piecewise linear approximation.
See also: | Signal Spectra 1 | Signal Spectra 2 | Pulse Spectra | LZI-System | Noise bandwidth demonstration | Amplitude modulation | Amplitude modulation (exercise in script) | AM transmitter 1 - record audio transmit signal to file | AM transmitter 2 - transmit recorded signal via USRP | Frequenzmodulation | Frequency modulation audio demo | FM transmitter (2) - transmit recorded signal from file to USRP |