Wave Walker DSP

DSP Algorithms for RF Systems

DSP: Intermediates

Matt Ettus on Fading Models

June 22, 2022

The 16-QAM constellation diagram.

Building a PSK and QAM Modulator in Python

June 8, 2022

Figure 7: Increasing the length of the signal by 2 improved the DFT frequency resolution by a factor of 2! Compare the frequency response of Figure 6, both of which have 8-point DFTs.

DFT Frequency Resolution Explained

March 16, 2022

Figure 2: The impulse response and frequency response of the LPF after the FIR filter gain is normalized to 0 dB at omega = 0.

Designing FIR Filter Gain

February 23, 2022

Figure 5: The impulse response of an odd length SRRC allows for optimal sampling by being able to select the peak at n=0. An even length SRRC filter does not.

Why an FIR Filter Should Have an Odd Length

December 29, 2021

Figure 4: The frequency domain for the real passband version of the BPSK signal with noise.

Efficient Real to Complex Conversion with a Half Band Filter

December 15, 2021

Figure 2: An example frequency response for a half band filter designed with halfBandDesign.py.

Half Band Filter Design Function in Python

December 8, 2021

Figure 2: The frequency responses for three different square root raised cosine filters.

Square Root Raised Cosine Filter in Python

November 10, 2021

Figure 4: The PFB half band filter structure after folding the even-symmetric filter weights hA[n] and ignoring the zero weights in hB[n].

Folding a Polyphase Half Band Filter: Lemon Squeezer Style

October 6, 2021

Figure 1: The weights of the partitioned half band filter hA[n] and hB[n].

Polyphase Half Band Filter for Decimation by 2

September 29, 2021

God, the Lord, is my strength; he makes my feet like the deer’s; he makes me tread on my high places. Habakkuk 3:19

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