I'tyring to generate a bit stream that will be modulated using an FSK signal. So far what I have is when I plotted the graph what I have is not an FSK signal but a bit stream.... bit = round(rand(1,10)); % bit stream of random 1's and 0's bitperiod = 0.1; %bit period fs = 11025; %sampling frequency fc = [1000 5000]; % carrier frequency % create the FSK signal transmitted = zeros(1,bit); for k = 1:length(bit) f = fc(bit(k) + 1); transmitted(floor((k1)*bitperiod*fs)+1: floor(k*bitperiod*fs)) = cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); % here's the trouble % I'm having. plot(transmitted) end Thanks guys for your help 

FSK modulation
Started by ●November 16, 2002
Posted by ●November 18, 2002
The code you gave gives an assignment error. Is that your problem. You have to rework the indices for transmitted and time values for cos(x). They both should be of same size which in your case is 1102. After that I got something which looks like a cosine wave. Navan  John <> wrote: > I'tyring to generate a bit stream that will be > modulated using an FSK > signal. So far what I have is when I plotted the > graph what I have > is not an FSK signal but a bit stream.... > > bit = round(rand(1,10)); % bit stream of random 1's > and 0's > bitperiod = 0.1; %bit period > fs = 11025; %sampling frequency > fc = [1000 5000]; % carrier frequency > % create the FSK signal > transmitted = zeros(1,bit); > for k = 1:length(bit) > f = fc(bit(k) + 1); > transmitted(floor((k1)*bitperiod*fs)+1: > floor(k*bitperiod*fs)) = > cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); % here's > the trouble > % I'm > having. > plot(transmitted) > end > > Thanks guys for your help __________________________________________________ 
Posted by ●November 18, 2002
Hi John,
in your code, you change the frequency f once a period. This is much too often. You better increase the sampling rate by x20 or so and create more samples, or in other words, vary the carrier frequency f much slower (linear interpolation or so) Servus Martin  Original Message  From: "John" <> To: <> Sent: Friday, November 15, 2002 1:58 PM Subject: [matlab] FSK modulation > I'tyring to generate a bit stream that will be modulated using an FSK > signal. So far what I have is when I plotted the graph what I have > is not an FSK signal but a bit stream.... > > bit = round(rand(1,10)); % bit stream of random 1's and 0's > bitperiod = 0.1; %bit period > fs = 11025; %sampling frequency > fc = [1000 5000]; % carrier frequency > % create the FSK signal > transmitted = zeros(1,bit); > for k = 1:length(bit) > f = fc(bit(k) + 1); > transmitted(floor((k1)*bitperiod*fs)+1: floor(k*bitperiod*fs)) = > cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); % here's the trouble > % I'm having. > plot(transmitted) > end > > Thanks guys for your help > > > _____________________________________ > Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer. You need to do a "reply all" if you want your answer to be distributed to the entire group. > > _____________________________________ > About this discussion group: > > To Join: > > To Post: > > To Leave: > > Archives: http://www.yahoogroups.com/group/matlab > > More DSPRelated Groups: http://www.dsprelated.com/groups.php3 > > ">http://docs.yahoo.com/info/terms/ 
Posted by ●November 18, 2002
Hi John, Enjoy it! bit = round(rand(1,10)); % bit stream of random 1's and 0's bitperiod = 1; %bit period fs = 20; %sampling frequency fc = [1 5]; % carrier frequency % create the FSK signal L=length(0:(bitperiod/fs):bitperiod); transmitted = zeros(1,L); for k = 1:length(bit) f = fc(bit(k) + 1); transmitted((k1)*L+1: k*L) = cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); stem(transmitted); end Best regards. digicomm  20021115 21:58:00 "John"<> wrote:  >I'tyring to generate a bit stream that will be modulated using an FSK >signal. So far what I have is when I plotted the graph what I have >is not an FSK signal but a bit stream.... > >bit = round(rand(1,10)); bit stream of random 1's and 0's >bitperiod = 0.1; bit period >fs = 11025; sampling frequency >fc = [1000 5000]; carrier frequency > create the FSK signal >transmitted = zeros(1,bit); >for k = 1:length(bit) > f = fc(bit(k) + 1); > transmitted(floor((k1)*bitperiod*fs)+1: floor(k*bitperiod*fs)) = >cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); here's the trouble > I'm having. >plot(transmitted) >end > >Thanks guys for your help > > >_____________________________________ >Note: If you do a simple "reply" with your email client, only the author of this message will receive your answer. You need to do a "reply all" if you want your answer to be distributed to the entire group. > >_____________________________________ >About this discussion group: > >To Join: > >To Post: > >To Leave: > >Archives: http://www.yahoogroups.com/group/matlab > >More DSPRelated Groups: http://www.dsprelated.com/groups.php3 > >">http://docs.yahoo.com/info/terms/ 

Posted by ●December 12, 2002
Hi digicomm I need help with my QPSK with a set of data bit to extract. I am having great difficulties in modulating and demodulating it. Would highly appreciate it if you have a sample program for me to learn how to do it. Your kind help is greatly appreciated. regards peter  digicomm <> wrote: > Hi John, > > Enjoy it! > > bit = round(rand(1,10)); % bit stream of random 1's > and 0's > bitperiod = 1; %bit period > fs = 20; %sampling frequency > fc = [1 5]; % carrier frequency > % create the FSK signal > L=length(0:(bitperiod/fs):bitperiod); > transmitted = zeros(1,L); > for k = 1:length(bit) > f = fc(bit(k) + 1); > transmitted((k1)*L+1: k*L) = > cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); > stem(transmitted); > end > > Best regards. > > digicomm > >  20021115 21:58:00 "John"<> > wrote:  > > >I'tyring to generate a bit stream that will be > modulated using an FSK > >signal. So far what I have is when I plotted the > graph what I have > >is not an FSK signal but a bit stream.... > > > >bit = round(rand(1,10)); bit stream of random 1's > and 0's > >bitperiod = 0.1; bit period > >fs = 11025; sampling frequency > >fc = [1000 5000]; carrier frequency > > create the FSK signal > >transmitted = zeros(1,bit); > >for k = 1:length(bit) > > f = fc(bit(k) + 1); > > transmitted(floor((k1)*bitperiod*fs)+1: > floor(k*bitperiod*fs)) = > >cos(2*pi*f*(0:(bitperiod/fs):bitperiod)); here's > the trouble > > I'm > having. > >plot(transmitted) > >end > > > >Thanks guys for your help > > > > > > > > > >_____________________________________ > >Note: If you do a simple "reply" with your email > client, only the author of this message will receive > your answer. You need to do a "reply all" if you > want your answer to be distributed to the entire > group. > > > >_____________________________________ > >About this discussion group: > > > >To Join: > > > >To Post: > > > >To Leave: > > > >Archives: http://www.yahoogroups.com/group/matlab > > > >More DSPRelated Groups: > http://www.dsprelated.com/groups.php3 > > > >">http://docs.yahoo.com/info/terms/ > > > > __________________________________________________ 
