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![Double Sideband Modulation (DSB):
One possible scheme for generating a DSBSC wave is to use two AM
modulators arranged in a balanced configuration so as to suppress the
carrier wave, as shown in above fig. Assume that two AM modulators are
identical, except for the sign reversal of the modulating signal applied to
the input of one of the modulators. Thus the outputs of the two AM
modulators can be expressed as follows:
S1 (t) = Ac [1+ka m(t)] cos 2fct
and
S2 (t) = Ac [1- ka m(t)] cos 2fct
Subtracting S2 (t) from S1 (t), we obtain
S (t) = S1 (t) – S2 (t)
S (t) = 2Ac ka m(t) cos 2fct](https://image.slidesharecdn.com/6mnlmwkvqscjmxi5a3pq-signature-e67a8a1e9d09d6356eaa5392502db46f92854db8faa740906c2235f677fa7bef-poli-141211130838-conversion-gate02/75/Single-side-band-and-double-side-band-modulation-6-2048.jpg)
![Hence, except for the scaling factor 2ka the balanced modulator output is equal
to product of the modulating signal and the carrier signal
The Fourier transform of s (t) is
S (f) = kaAc [M (f-fc) + M (f+fc)]
Assume that the message signal is band-limited to the interval –W ≤f≤ W](https://image.slidesharecdn.com/6mnlmwkvqscjmxi5a3pq-signature-e67a8a1e9d09d6356eaa5392502db46f92854db8faa740906c2235f677fa7bef-poli-141211130838-conversion-gate02/75/Single-side-band-and-double-side-band-modulation-8-2048.jpg)
Uploaded byMd. Hasan Al Roktim
Single side band and double side band modulation
The document presents information on single sideband (SSB) and double sideband (DSB) modulation using a balanced modulator method. It discusses how SSB splits the modulating signal into two identical signals, with one passing through a 90 degree phase shifter before modulating the quadrature carrier. It also explains how DSB suppression works by using two AM modulators with an inverted modulating signal to one, so that subtracting their outputs removes the carrier wave. The document concludes by thanking all the attendees of the presentation.
In this document
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Introduction to the presentation and presenters, outlining topics on SSB and DSB modulation.
Explanation of SSB, where the modulating signal is split and affects carrier phase, determining USB or LSB.
Description of DSB modulation using balanced modulators, showing signal expressions and output relations.
Acknowledgment and thanks to the audience for their attention.
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Single side band and double side band modulation
- 1. Welcome To OurPresentation
- 2. Presentation Topics SingleSide Band (SSB) & Double Side Band (DSB) Modulation by using Balanced Modulator Method.
- 3. Presented By Name Md. Hassan Al Roktim Md. Abu Imran Md. Harun-Ar-Rashid ID 121-33-893 121-33-859 121-33-879
- 4. Single Sideband Modulation(SSB): The modulating signal is split into two identical signal. Which modulates the phage carrier and the other which is passed through a -90˚ phage shifter before modulating quadrature carrier. The sign used for the quadrature component determines whether USB or LSB is transmitted.
- 5.
- 6. Double Sideband Modulation(DSB): One possible scheme for generating a DSBSC wave is to use two AM modulators arranged in a balanced configuration so as to suppress the carrier wave, as shown in above fig. Assume that two AM modulators are identical, except for the sign reversal of the modulating signal applied to the input of one of the modulators. Thus the outputs of the two AM modulators can be expressed as follows: S1 (t) = Ac [1+ka m(t)] cos 2fct and S2 (t) = Ac [1- ka m(t)] cos 2fct Subtracting S2 (t) from S1 (t), we obtain S (t) = S1 (t) – S2 (t) S (t) = 2Ac ka m(t) cos 2fct
- 7.
- 8. Hence, except forthe scaling factor 2ka the balanced modulator output is equal to product of the modulating signal and the carrier signal The Fourier transform of s (t) is S (f) = kaAc [M (f-fc) + M (f+fc)] Assume that the message signal is band-limited to the interval –W ≤f≤ W
- 10.