BPSK Modulator

Balanced Ring Modulator

Note: fm = fb/ 2 fb - input bit rate

BANDWIDTH :

• A balanced modulator is a product modulator

Output = ( sin w mt ) ( sin w Ct )

But we know that, Sin A Sin B = ½[ cos (A -B) -cos (A +B)]

Therefore,

Output = ½[ cos (wc-wm )t - cos( wc + wm)t ]

It follows that ,

    Lower Side Frequency = wc- wm
    Upper Side Frequency = wc + wm

The minimum double-sided Nyquist Bandwidth (BWN) is:

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