DSSS Direct Sequence Spread Spectrum

Spread signal bandwidth using PN sequence

Real-World Applications

WiFi (802.11b) legacy 1/2Mbps mode, Zigbee smart home protocol, GPS navigation signals. Using pseudo-noise sequences to spread energy across a wide frequency band, extremely interference-resistant, can even transmit below noise (covert communication).

Experiment Steps

Processing Gain: Gp = Chip Rate / Data Rate
Anti-jamming: Can operate under negative SNR

Simulation Experiment

Time Domain (X: Time, Y: Amplitude)

Spectrum Analysis (X: Frequency, Y: Amplitude)

DSSS Anti-Jamming & LPI Demo

DSSS Anti-Jamming Demo

Processing Gain (Gp): 10 (Chip Rate / Data Rate)

Observe how integration decision extracts signal from noise at very low SNR.

Jammer:Power: 0.0 (Try increasing interference, observe if despread signal remains clear)

Parameters(Real-time)

Data Rate50 bps

Chip Rate500 cps

SNR0 dB

Functions: models.phy.pnSequence, models.phy.dsssSpread

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