Binary Phase Shift Keying ( BPSK ) Demodulation

Calculations & Observations




Fig.1 Demodulation of BPSK Signal.

The demodulated wave is obtained after again being multiplied with the carrier wave of same frequency & the demodulated wave can be made more distortion free by varying the LPF gain & frequency.





Fig.2 Frequency Spectrum of Demodulation of BPSK signal.

The frequency spectrum has THD (Total Harmonic Distortion) of 141.58 % & SINAD of 0.01 dB . The detected fundamental frequency is 881.42 Hz & the corresponding Power is 4.99.





Fig.3 Power spectrum of demodulation of BPSK Signal.

It is common for radio frequency communications systems to be upset by unwanted electromagnetic radiation called noise. Some of this radiation occurs naturally and is generated by the Sun and atmospheric activity such as lightning. Much of the radiation is human-made - either unintentionally the electromagnetic radiation given off by electrical machines and electronics equipment or intentionally other peoples' communication transmissions that we don't want to receive.

Most noise gets added to signals while they're in the channel. This changes the signals' shape which in turn changes how the signals sound when demodulated by the receiver. If the noise is sufficiently large relative to the size of the signal the signal can be changed so much that it cannot be demodulated.

The Power Spectrum has THD as 172.06 % & SINAD is 0.13 dB. The detected fundamental frequency is at 678.94 Hz & the corresponding power is 4.65.