T
tal
Guest
hi
i'm doing a project and i need a vhdl code for 16 qam modulation.
thanks
i'm doing a project and i need a vhdl code for 16 qam modulation.
thanks
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N
Nicolas Matringe
Guest
tal a écrit:
with quadrature carriers...
2 hours work at worst. Come on, you can do it can't you?
--
____ _ __ ___
| _ \_)/ _|/ _ \ Adresse de retour invalide: retirez le -
| | | | | (_| |_| | Invalid return address: remove the -
|_| |_|_|\__|\___/
Shouldn't be too hard to do, that's just two identical AM modulators fedhi
i'm doing a project and i need a vhdl code for 16 qam modulation.
with quadrature carriers...
2 hours work at worst. Come on, you can do it can't you?
--
____ _ __ ___
| _ \_)/ _|/ _ \ Adresse de retour invalide: retirez le -
| | | | | (_| |_| | Invalid return address: remove the -
|_| |_|_|\__|\___/
T
tal
Guest
Nicolas Matringe <matringe.nicolas@numeri-cable.fr> wrote in message news:<407647AA.7060100@numeri-cable.fr>...
i did the vhdl code for the maping but i dont known how to convert the
i an q bits to sine wave.
Anyone could help?
thanks.
hital a écrit:
hi
i'm doing a project and i need a vhdl code for 16 qam modulation.
Shouldn't be too hard to do, that's just two identical AM modulators fed
with quadrature carriers...
2 hours work at worst. Come on, you can do it can't you?
i did the vhdl code for the maping but i dont known how to convert the
i an q bits to sine wave.
Anyone could help?
thanks.
G
Guenter
Guest
tal wrote:
with FPGA, maybe that helps.
http://www.andraka.com/papers.htm
Guenter
Andraka consulting has a paper about modulation/demodulation techniquesNicolas Matringe <matringe.nicolas@numeri-cable.fr> wrote in message news:<407647AA.7060100@numeri-cable.fr>...
tal a écrit:
hi
i'm doing a project and i need a vhdl code for 16 qam modulation.
Shouldn't be too hard to do, that's just two identical AM modulators fed
with quadrature carriers...
2 hours work at worst. Come on, you can do it can't you?
hi
i did the vhdl code for the maping but i dont known how to convert the
i an q bits to sine wave.
Anyone could help?
thanks.
with FPGA, maybe that helps.
http://www.andraka.com/papers.htm
Guenter
R
Ray Andraka
Guest
I did have a QAM64 example in a prior incarnation of that presentation. That one doesn't have it in there.
Basically, you need to pass the I and Q bits through a nyquist filter (this is just an FIR filter with a usually
root raised cosine response). You'll need to upsample as you filter, which is equivalent to stuffing zeros between
each IQ sample and then low pass filtering. It is more efficiently done as a polyphase interpolating filter, which
lets the filter work at the IQ rate rather than the upsampled rate. The filtered IQ is your complex baseband.
You'll mix that with a complex exponential (sine and cosine) to get your IF or broadcast carrier. If you can set
the sample rate of the IQ to be 4x the carrier (or IF) then the mixer's local oscillator is 1,j,-1,-j, which can be
accomplished with a pair of adder/subtractors.
tal wrote:
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email ray@andraka.com
http://www.andraka.com
"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759
Basically, you need to pass the I and Q bits through a nyquist filter (this is just an FIR filter with a usually
root raised cosine response). You'll need to upsample as you filter, which is equivalent to stuffing zeros between
each IQ sample and then low pass filtering. It is more efficiently done as a polyphase interpolating filter, which
lets the filter work at the IQ rate rather than the upsampled rate. The filtered IQ is your complex baseband.
You'll mix that with a complex exponential (sine and cosine) to get your IF or broadcast carrier. If you can set
the sample rate of the IQ to be 4x the carrier (or IF) then the mixer's local oscillator is 1,j,-1,-j, which can be
accomplished with a pair of adder/subtractors.
tal wrote:
--Nicolas Matringe <matringe.nicolas@numeri-cable.fr> wrote in message news:<407647AA.7060100@numeri-cable.fr>...
tal a écrit:
hi
i'm doing a project and i need a vhdl code for 16 qam modulation.
Shouldn't be too hard to do, that's just two identical AM modulators fed
with quadrature carriers...
2 hours work at worst. Come on, you can do it can't you?
hi
i did the vhdl code for the maping but i dont known how to convert the
i an q bits to sine wave.
Anyone could help?
thanks.
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email ray@andraka.com
http://www.andraka.com
"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759