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implementing on dsp

Started by Zeph80 March 6, 2009
I have to implement several QPSK narrowband carriers 24 ksym/sec,32Khz BW
 I have several basic questions since I've haven't worked with DSPs
before and am in the process of data collection before I pick a processor.

1. I want to do several of these channels in 1 dsp,since I will only be
doing scrambling,encoding, and pulse shaping(oversampling by 5) then output
I and Q at baseband  each going to an I and Q DAC at 160 Ksym/sec Fs for
each channel.

Can I do this 1 dsp, and output multiple low bit rate baseband I and Q
samples to different DACs?
 Each channel is operating at 24Kysm/sec and oversampled 5.Is this a
specific kind of dsp I need.Also can i just calculate the MIPS by
considering 160Ksym *2(I and Q) as the sample rate and then multiply  the
no. of chainswith no of MIPS per chain.

 2. I need to eventually have all these translated to an IF of 60-70 MHZ.
 I initially wanted to have all channels upconverted to a low frequency
500Khz before going into the DAC ( operating at some Fs of 1.5Mhz) and the
use a far out image as IF . However I haven't done this and I dont know if
its feasible.Can anyone point me to links for how to do this for several
low bit rate carriers


Zeph80 wrote:

> I have to implement several QPSK narrowband carriers 24 ksym/sec,32Khz BW > I have several basic questions since I've haven't worked with DSPs > before and am in the process of data collection before I pick a processor.
Since evidently you are student and you have no slightest clue, pick the PIC. Start with the basics and gain some experience. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
On Mar 6, 6:49&#2013266080;pm, "Zeph80" <surabhi_tal...@hotmail.com> wrote:
> I have to implement several QPSK narrowband carriers 24 ksym/sec,32Khz BW > . I have several basic questions since I've haven't worked with DSPs > before and am in the process of data collection before I pick a processor. > > 1. I want to do several of these channels in 1 dsp,since I will only be > doing scrambling,encoding, and pulse shaping(oversampling by 5) then output > I and Q at baseband &#2013266080;each going to an I and Q DAC at 160 Ksym/sec Fs for > each channel. > > Can I do this 1 dsp, and output multiple low bit rate baseband I and Q > samples to different DACs? > . Each channel is operating at 24Kysm/sec and oversampled 5.Is this a > specific kind of dsp I need.Also can i just calculate the MIPS by > considering 160Ksym *2(I and Q) as the sample rate and then multiply &#2013266080;the > no. of chainswith no of MIPS per chain. > > &#2013266080;2. I need to eventually have all these translated to an IF of 60-70 MHZ. > &#2013266080;I initially wanted to have all channels upconverted to a low frequency > 500Khz before going into the DAC ( operating at some Fs of 1.5Mhz) and the > use a far out image as IF . However I haven't done this and I dont know if > its feasible.Can anyone point me to links for how to do this for several > low bit rate carriers
Here is a book that discusses communication applications in TI 320C67x floating point DSPs., probably it is a good reference for you: http://www.amazon.com/Communication-System-Design-Using-Algorithms/dp/0306474298/ref=sr_1_17?ie=UTF8&s=books&qid=1236500283&sr=1-17