Spectral Properties of Square Wave Signals
1. Time domain period, frequency discrete ()
2. Signal spectrum (phase spectrum, amplitude spectrum)
3. The signal wave has a Gipps phenomenon when it rises or falls () Because the impulse response function in the actual calculation can only take a finite length, that is, it needs to be truncated, and the frequency response function corresponding to the truncated impulse response is no longer an ideal one. " Gate ", but a curve with fluctuating amplitude close to such a gate, a phenomenon called Gipps phenomenon.
4. The higher the frequency, the smaller the amplitude
5. Spectral envelope
6.f1=10f2, the amplitude difference is -20dB (every 10 co-frequency multiplied by -20dB attenuation)
7. Bandwidth is pulse width, duty cycle (set, represented by the letter τ )
Knowledge points:
1. Spectral characteristics of digital signals
2. Periodic signals can be decomposed into a series of combinations of sine and cosine waves, decomposing Fourier
3. An ideal square wave can be decomposed into a series of sine waves
4. The envelope of the ideal square wave signal spectrum is a straight line, 1/πτ is the turning point of the frequency point, and the attenuation is -20dB for every 10 subbands after the frequency point.