CONCEPT OF BINARY PHASE SHIFT KEYING TO BPSK, 8 PSK, 16 PSK
CONCEPT OF BINARY PHASE SHIFT KEYING:
Binary Phase Shit Keying(BPSK)
Principle o BPSK
In binary phase shit keying (BPSK), binary symbol ‘1’ and ‘0’ modulate the phase of the carrier. Let the carrier be,
‘A’ represents peak value of sinusoidal carrier. In the standard 1Ω load register, the power dissipated will be
When the symbol is changed, then the phase o the carrier is changed by degree (π radians)
Consider for example
Graphical Representation of BPSK Signal
Fig 4.2.1 shows binary signal and its equivalent signal b(t).
As can be seen from Fig. 4.2.1 (b), the signal b(t) is NRZ bipolar signal. This signal directly modulated carrier cos(2πf0t)
The BPSK signal can be generated by applying carrier signal to the balanced modulator.
The baseband signal b(t) is applied as a modulating signal to the balanced modulator. Ig 4.2.2 shows the block diagram of BPSK signal generator.
The NRZ level encoder converts the binary data sequence into bipolar NRZ signal.
Reception of BPSK Signal
Fig 4.2.3 shows the block diagram of the scheme to recover baseband signal from BPSK signal. The transmitted BPSK signal is,
Note here that we have neglected the amplitude, because we are only interested in the carrier of the signal.
Bandwidth of BPSK Signal
Thus the minimum bandwidth of BPSK signal is equal to twice of the highest frequency contained in baseband signal.