## is there someone having 2812's UCOS SOURCE CODE?

Digital Signal Processing

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• 1. SI System urged to adopt "hella"
Various news stories report the following: "In early 2010, Austin Sendek of UC Davis created a petition encouraging the SI system to designate "hella-" as the prefix for 10^27, following "yotta-" for 10^24." (Some sources mistakenly state that Sendek would like the nubmer 10^27 to be referred to as "a hella"; but this is not the case, and is obviously not even remotely grammatical.) Steve
• 2. Fair comparison between time domain equalizer and OFDM
Hi All So far I have worked on time domain equalizers such as LE and DFE. Recently I have started to work on OFDM systems. And I am trying to compare the performance for Proakis channel B which is three tap channel. First system: map the info bits to BPSK, pass the symbols through channel, add noise. The channel output I write it as y=conv(h,x)+noise, where h=[0.407 0.815 0.407] and x= +/- 1. At receiver perform LE using MMSE under the assumption that the channel is knonwn at the receiver. I get the exact BER plot given in Proakis comms edition 4. Second system: map the info bits to BPSK, perform IFFT, add cyclic prefix, pass it through channel and add noise. The channel output y=conv(h,x)+noise, where x=IFFT(X,N), X=+/- 1 and N=2048. At receiver, remove the CP, truncate the signal and performe one tap MMSE equalization i.e. \hat{X}=fft(H,N)/fft(y,N) and then take hard decision on real part. The problem is that the BER of system 2 is way off when compared to the BER of system 1. As a test case, when I removed the noise from system 2, I get 0 BER. Furthermore, when I put h=1 in system 2, I get the exact plot of BPSK on AWGN. Any idea on what I might be doign wrong? Your help is greatly appreciated. Regards Chintan
• 3. Definition of BT in an FSK system
BT denotes the product of the 3 dB bandwidth of the shaping pulse in an FSK system and the symbol time. My question has to do with the conventional definition of B. My first thought was to use the 3 dB bandwidth of a bandpass function obtained by translating the baseband pulse up to the FSK center frequency; or equivalently, twice the bandwidth (from 0 Hz to the 3 dB point) of the pulse viewed as a lowpass function at baseband. However, doing it this way results in a curve that disagrees with some published shaping curves; it appears people (in at least some cases) leave the factor of two out, and just look at the bandwidth of the lowpass function, from 0 Hz to the positive 3 dB point. What is the convention here? Thanks, Steve

### is there someone having 2812's UCOS SOURCE CODE?




Hi,

I was asked to do some research on this "hamming code" and compare its
efficiency with huffman coding? But i remember from my class and
context
book, hamming code is some kind of error correction channel coding
scheme.
As I right? if yes, how can I compare the efficiency of a channel
coding to source coding? I have already thrown away all my knowledge
from classroom.

Thanks


Hi,
I am trying to setup a 2812 to take A to D readings. I have the ADC
and to branch to the ADC interrupt at the EOS (end of sequence). When
the program branches to the interrupt routine, I read and store the
result registers to variables. My problem is that the result registers
never change their value even when I vary the applied signal between 0V
and 3V. Any suggestions? Also, I have the ADC set to suspend mode0
where an emulation suspend is ignored (i.e. the ADC continues to sample
even when I hit a breakpoint?). Would this have anything to do with it?
Alex



Hello !
Would someone be able to explain me how to calculate the execution time o
a
NOP instruction when it is executed into flash and into external ram of
DSP
TI 2812?
Is it normal to have a time more important (2*) into ram than into flas
?
Is it normal to see that a change into the configuration of XINTF doesn'

change the execution time ?



Hi all,

This is regarding flashing a code in 2812 processor from TI. I tried
flashing a sample code from spectrum digital using the SDFlash
utility. I was able to flash it a couple of times, but after that it
was consistently showing errors in flashing. Actually the probelm was
with locking and unlocking the device using CSM.

The important point to be noted as far as flashing is concerned is
that the device has to be reset once ( soft reset thru the SDFlash
utility ) and then flashed, but not the reverse. In case u accidently
reset the device after flashing, it places 0000 in all the password
locations and locks the device permanently and after that ur device
cannot be debugged or reprogrammed. In case u r using an eZDSP kit
continue working with onchip and off chip RAM, but secure RAM