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frequency spectrum plot (frequency modulation)

Started by bos1234 in comp.dsp14 years ago 2 replies

when freq.spectrum is plotted for FM signals such as the pic below, how would I go about calculating the power? Is it sum of |X(f)|^2 (i.e....

when freq.spectrum is plotted for FM signals such as the pic below, how would I go about calculating the power? Is it sum of |X(f)|^2 (i.e. square each individual compnent and add) The solution has the solution squares each indivial compnents adds it then halves (i.e. 1/2 . A_c^2). Why did they do this?


V.27ter

Started by Luiz Carlos in comp.dsp19 years ago 5 replies

I need some help on the V.27ter modulator (PSK). At 4800 bps we have: Modulation frequency fm=1800[Hz] Symbol/baud rate fb=1600[Hz]...

I need some help on the V.27ter modulator (PSK). At 4800 bps we have: Modulation frequency fm=1800[Hz] Symbol/baud rate fb=1600[Hz] (symbol/s) Let's suppose the follow spectrum for the symbols: Obs.: I will keep a small part of the negative spectrum just for a better visualization. /|\ / | \ / | \ +-------+-------+ | | 0 fb/2=800[Hz...


CPFSK and spreading

Started by Anonymous in comp.dsp18 years ago

Hi, I am trying to simulate the process of spreading with CPFSK modulation. Can anybody tell me what effect will it have? The problem i am...

Hi, I am trying to simulate the process of spreading with CPFSK modulation. Can anybody tell me what effect will it have? The problem i am facing is that even if the spreading sequence is not applied at the demodulator portion, the sequence is demodulated correcly. The simulation is being done in System View. If anybody can help me, please guide me. Thanks


Help - brain block!

Started by rufus in comp.dsp20 years ago 7 replies

Hello, If someone could just point me in the right direction I would appreciate it. I have built a real-time signal modulation simulator. I...

Hello, If someone could just point me in the right direction I would appreciate it. I have built a real-time signal modulation simulator. I extract data from the sound card buffer, modulate it, then display it freq components on a GUI (spec an). Here is my dilema. I am trying to do ssb - I have the formula. Now what is the easiest way to convert the real samples into complex numbers? Curre...


FSK Demodulator

Started by biff in comp.dsp16 years ago 14 replies

Hi folks, I manage a hardware engineering group for a telcom company and I am beginning to look around for FPGA IP to implement both FSK...

Hi folks, I manage a hardware engineering group for a telcom company and I am beginning to look around for FPGA IP to implement both FSK modulation and demodulation. I am wondering if any of you have any experience with any of the IP around today. The demodulator is the most difficult part and I believe the following list of requirements is fairly close: * 300 KHz bandwidth * 5-21 MHz ...


Inverted Video

Started by Anonymous in comp.dsp17 years ago 15 replies

"Simon S Aysdie" wrote > Why is video inverted for transmission? So that the peaks of sync pulses are transmitted at +100%...

"Simon S Aysdie" wrote > Why is video inverted for transmission? So that the peaks of sync pulses are transmitted at +100% modulation, which allows TV receivers to show the most stable picture in the presence of noise (eg, fringes of the coverage area of the TV station). RF RCA Broadcast Field Engineer, retired


Normalizing Histogram

Started by cpshah99 in comp.dsp15 years ago 3 replies

Dear All I am trying to plot histogram of the o/p of equalizer. As the o/p is complex I will have to plot histogram of real and imaginary...

Dear All I am trying to plot histogram of the o/p of equalizer. As the o/p is complex I will have to plot histogram of real and imaginary part separately. I know it is straight forward in matlab, but the problem is how to normalize y-axis. The modulation I am using is 4-QAM. As this will be bimodal distribution around +1 and -1, I am thinking to do following: 1. find std deviation (\sigma...


Bandwidth and Bauds...

Started by ifmusic in comp.dsp17 years ago 4 replies

i had a looong discution over a Math group where i was encouraged to post Here. So, i know this: i have a digital signal which has 10...

i had a looong discution over a Math group where i was encouraged to post Here. So, i know this: i have a digital signal which has 10 PulsesPerSecond, i have a modulation speed=50Bauds. Ok, what i need to find out is: -which is the bandwith requiered to send this signal. -the fourier spectrum Things that i was able to find out: for this signal, frecuency=10hz since period T=1/PperSecond...


pi/4-shifted QPSK

Started by hiroki in comp.dsp13 years ago 5 replies

Hi everyone, I have a question regarding the pi/4-shifted QPSK modulation. I have been reading a lot of websites, including this forum, but I...

Hi everyone, I have a question regarding the pi/4-shifted QPSK modulation. I have been reading a lot of websites, including this forum, but I still cannot get the answer. Regarding pi/4 shifted QPSK, which is the correct one? (1) Phase is shifted pi/4 after every symbol. This means that even if the same word is transmitted, the point on the constellation will shift by pi/4 everytime.. ...


Hi - Need Suggestion

Started by asridhareng in comp.dsp15 years ago 1 reply

Dear Friends, Till now I am doing on Speech/Audio Coding Implementations on various DSP's. I am thinking to change my domain to Wireless...

Dear Friends, Till now I am doing on Speech/Audio Coding Implementations on various DSP's. I am thinking to change my domain to Wireless Communication, specifically to base band processing and modulation side. I need how to start this? When even I type in the internet I am getting plenty of stuff and don't know what and how to start. I will be glad if any body can give suggestions on thi...


GMSK pulse shaping

Started by mathew in comp.dsp19 years ago 2 replies

Hi there. I am currently persuing a Msc Eng degree from the university of Natal,Durban, South Africa. Recently I have been working on a system...

Hi there. I am currently persuing a Msc Eng degree from the university of Natal,Durban, South Africa. Recently I have been working on a system of which the simulation results are given for the Edge standard. The author of this paper however specifies that the 8psk modulation is infact used for the results. He does however add that the channel is that of a typical urban (TU) channnel with linear...


Communications - out of band suppression?

Started by Chris Maryan in comp.dsp16 years ago 9 replies

I realize this is a bit of a fuzzy question that warrants a nebulous answer, but I'm looking for orders of magnitude. In most real world...

I realize this is a bit of a fuzzy question that warrants a nebulous answer, but I'm looking for orders of magnitude. In most real world communications systems, when filtering in on a band of interest, what is the typical level of attenuation of neighbouring bands? How much does this vary for different modulation schemes? The reason I ask is that I'm playing around with implementing a r...


Getting the most information in a limited number of transitions

Started by Tim Wescott in comp.dsp10 years ago 16 replies

If wishes were horses, then after writing this I'd have one hell of a feed bill: Say that I have a modulator that can transmit bi-valued...

If wishes were horses, then after writing this I'd have one hell of a feed bill: Say that I have a modulator that can transmit bi-valued information -- let it be -1 and 1 for the sake of argument. I can transition from one state to the other any time that I want, but each transition carries a cost -- so I want to design a modulation scheme that maximizes the amount of information tha...


need Bpsk and qpsk modulation

Started by Muizz83 in comp.dsp13 years ago

I need matlab or simulink programer who can write a code, person must know about signal processieng , BPSK, QPSK in matlab, how to generate...

I need matlab or simulink programer who can write a code, person must know about signal processieng , BPSK, QPSK in matlab, how to generate and modulate signal. Kindly contact with me.


16-QAM modulation output values

Started by Anonymous in comp.dsp16 years ago 6 replies

Hi, In my 16-QAM constellation the symbol 0011 at located at I=1, Q=3. What binary or hex value do I output for 1 and 3 if I am using say...

Hi, In my 16-QAM constellation the symbol 0011 at located at I=1, Q=3. What binary or hex value do I output for 1 and 3 if I am using say 16 bit signed binary? Can I use say 7FFFh for 3 and e.g. 2AAAh for 1? Are standards available to show what values should be used? Many Thanks Bob


16-QAM modulation output values

Started by Anonymous in comp.dsp16 years ago

Hi, In my 16-QAM constellation the symbol 0011 at located at I=1, Q=3. What binary or hex value do I output for 1 and 3 if I am using say...

Hi, In my 16-QAM constellation the symbol 0011 at located at I=1, Q=3. What binary or hex value do I output for 1 and 3 if I am using say 16 bit signed binary? Can I use say 7FFFh for 3 and e.g. 2AAAh for 1? Are standards available to show what values should be used? Many Thanks Bob


Advantages of Gray Coding for QAM

Started by Deamon in comp.dsp13 years ago 29 replies

I have been reading about QAM modulation and wondering when I gray code what advantage is that for my BER as the SNR increases Is there much...

I have been reading about QAM modulation and wondering when I gray code what advantage is that for my BER as the SNR increases Is there much difference for a 16 QAM system or this effect does not help at all at 16 QAM system. Any reference would be appreciated.


Channel Length Modulation in MOS Circuit Design

Started by Randy Yates in comp.dsp16 years ago 1 reply

I've had some long-standing confusion in this subject and decided to write a paper to attempt to clarify things for myself. I'd be interested to...

I've had some long-standing confusion in this subject and decided to write a paper to attempt to clarify things for myself. I'd be interested to see if others think I'm completely off-track or think my points are valid. http://galois.digitalsignallabs.com/channellengthmodulation.pdf PS: I know there's a lot of sharp, eclectic engineers on comp.dsp, hence my cross-post there. -- % R...


selection of Fpga

Started by kumari in comp.dsp16 years ago 1 reply

Hi i'm new to using Fpga.My project is design of modulator using Fpga based on Dsp technology.My data rate is 12Mb and Intermeadiate freq is...

Hi i'm new to using Fpga.My project is design of modulator using Fpga based on Dsp technology.My data rate is 12Mb and Intermeadiate freq is 140 Mhz. I decided to use D8psk modulation technique. i want to choose Fpga for this design.which parameters have to be considered for choosing fpga.


SSB modulator

Started by sekhar in comp.dsp18 years ago 2 replies

Hi all, I am a newcomer to DSP and MATLAB. Can anyone help me with matlab code for SSB modulator( IQ modulator). I want to am simulate BPSK and...

Hi all, I am a newcomer to DSP and MATLAB. Can anyone help me with matlab code for SSB modulator( IQ modulator). I want to am simulate BPSK and AM modulation. Thanks Sekhar