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lokesh anand
Joined: 26 Jul 2006
Posts: 31
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 27 Jul 2006 11:49 Quadri-Phase Shift Keying (QPSK) |
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| tell me about what is Quadri-Phase Shift Keying (QPSK) modulation scheme for digital transmission all about?
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shameem
Joined: 27 Oct 2005
Posts: 139
Helped: 2
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| 27 Jul 2006 12:37 Re: Quadri-Phase Shift Keying (QPSK) |
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hi,
in dqpsk modulation, we transmit two bits of digital data on a phase which is pi/4 or odd multiple of it like 3*pi/4, 5*pi/4..........
Since in this modulationwe transmit two bits on a single carrier, this technique is relatively more efficient in data transmission.
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HMZ
Joined: 06 Jan 2004
Posts: 37
Helped: 2
Location: Earth,Iran,Tehran unfortunately
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| 30 Jul 2006 20:34 Re: Quadri-Phase Shift Keying (QPSK) |
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from Proakis ch 4 p 171
in Mpsk signals' formula is
sm(t)=g(t) cos[2πfct+2π(m-1)/M]
for m=1 ,2,...,M ,fc is central freq and g(t) is pulse shape say rect pulse
it means that you have M diffrent signal that differ in phase as is clear in second term of bracket
in qpsk we have M=4 and phases will be 0 ,π/2,π,3π/2
viva Persia
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Murtuza Marketwala
Joined: 27 Jul 2006
Posts: 5
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| 31 Jul 2006 14:36 Re: Quadri-Phase Shift Keying (QPSK) |
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hi this is an useful document on the QPSk.
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lokesh anand
Joined: 26 Jul 2006
Posts: 31
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| 09 Aug 2006 12:36 Re: Quadri-Phase Shift Keying (QPSK) |
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| thanks a lot for your help. those infomation will be very useful for me.thanks
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ahmedseu
Joined: 31 Jul 2006
Posts: 231
Helped: 20
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| 09 Aug 2006 12:40 Re: Quadri-Phase Shift Keying (QPSK) |
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These files are for QPSK modulator and soft-output demodulator.
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