## Forums Search for: Demodulation

## Single Side Band (SSB) Demodulation

inHello Every One! Actually I am working on Single Side Band (SSB) Modulation/Demodulation. I have successfull programmed the Modulator...

Hello Every One! Actually I am working on Single Side Band (SSB) Modulation/Demodulation. I have successfull programmed the Modulator and the Demodulator. But Now I have one problem, that I want extract the Carrier Frequency from the SSB (transmitted) signal at the receiver end. Any one can guide my in the respect. Thanks.......................... ____________________________________...

## System Sensitivity based on Power Spectral Density

inHi all, I hope you can help me with this problem because I'm really confused by it at this stage. I have implemented a demodulation scheme...

Hi all, I hope you can help me with this problem because I'm really confused by it at this stage. I have implemented a demodulation scheme on a dsp processor and I'm currently trying to establish the sensitivity in terms of radians per root Hz. The signal before demodulation is - cos(cos(2*PI*8kHz*t) + s(t)) The demodulated signal is of the form - s(t) The signal prior to d...

## modulation/demodulation - orthogonal fonctions

inHi all, Im working on an (synthetic) acoustic experiment: I have a receiver that records waves emitted by two sources S1 and S2. So the...

Hi all, Im working on an (synthetic) acoustic experiment: I have a receiver that records waves emitted by two sources S1 and S2. So the receiver records R=S1+S2. I would like to "filter" R to get only S1 or S2. Is there any way of doing that ?? S1 and S2 are defined in the same frequency band. So i cannot use a simple filter. Im thinking about modulating/demodulation the signals ...

## Carrier recovery for FSK demodulation

inHi everbody, I'm new in the field of "synchonization" concerning all-digital receivers. At the moment I'm working at the problem of...

Hi everbody, I'm new in the field of "synchonization" concerning all-digital receivers. At the moment I'm working at the problem of "frequency offset correction". While there is a frequency offset between the LO of the transmitter and the LO of the receiver, I've to determine the offset due to perform a proper convertion of the received signal into complex baseband for demodulation. (I'd l...

## Demodulation with Hilberttransformation

inHello, Using " highpass | rectify | lowpass | downsample" for ages to demodulate signald, I've just found that demodulation using...

Hello, Using " highpass | rectify | lowpass | downsample" for ages to demodulate signald, I've just found that demodulation using Hilberttransformation seems to be very easy (speaking matlab/octave): function y=demodulate( x ) y=sqrt(x.^2 + real(hilbert(x)).^2); endfunction (I implemented "hilbet" myself, using fft) That's the "how", easy ;) But I do not understand the "why". I u...

## BPSK demodulation

inHi,everyone I'm kind of a newbie in everything relatated to modulation/demodulation and as I am now working with it on Matlab, I'm just...

Hi,everyone I'm kind of a newbie in everything relatated to modulation/demodulation and as I am now working with it on Matlab, I'm just learning it by myself. With the amplitude modulation I get by, but I now have to demodulate a BPSK modukated signal and I don't really know how to do it. What I have is a 847KHz signal (actually it's the side band signal) modulated with what I think is t...

## Classic FM Demodulation, using Matlab

inI've got a real voltage versus time waveform (e.g. xr) of a carrier frequency that is FM modulated. I need to see the modulation waveform...

I've got a real voltage versus time waveform (e.g. xr) of a carrier frequency that is FM modulated. I need to see the modulation waveform to determine its peak-to-peak amplitude. While I do see a lot of code online for FM demodulation, I'm hesitant to use it unless I can understand it from first principles. The method that makes most sense to me is the equation I see in Rick Lyon's excellent book ...

## Complex AM demodulation- simple question

inTo demodulate AM, I use the formula am = sqrt(I*I + Q*Q) I am mixing an AM IF signal to baseband, i.e. carrier plus 2 sidebands. My test signal...

To demodulate AM, I use the formula am = sqrt(I*I + Q*Q) I am mixing an AM IF signal to baseband, i.e. carrier plus 2 sidebands. My test signal is modulated at 800Hz. When I look at the demodulation, it looks OK when I mix perfectly to 0Hz, but as the transmitted signal moves up or down frequency, I end up with 2 frequencies in the demodulated signal. i.e. I get a demodulated signal of 200H...

## Software Pulse Amplitude Demodulation

inHi all, I am doing a simple demodulation of a sampled RF signal. I set my digitizer at a fixed 1 GS/s. I don't know what my carrier will be,...

Hi all, I am doing a simple demodulation of a sampled RF signal. I set my digitizer at a fixed 1 GS/s. I don't know what my carrier will be, but it will be less that 200MHz. The signal is pulse amplitude modulated, and I want to recover the original signal. To do this, I have applied a Hilbert transform, and then derived the magnitude which gives me a good approximation of the encoded signa...

## FSK coherent demodulation in Rayleigh Fading Channel

inWe know coherent and noncoherent FSK demodulation can be done by using correlator and energy detector. In Fading channel case with noncoherent...

We know coherent and noncoherent FSK demodulation can be done by using correlator and energy detector. In Fading channel case with noncoherent demodulation, we can use the energy detector. But in coherent case, how could we use the channel state information to detect signal..... BFSK: h is the channel fading...x is the transmitted signal...n# is noise in channel# rx1 = hx + n1 rx2 = n2...

## Gbps BPSK demodulation

inHi all, I'm looking for an architecture dedicated to a Gbps BPSK demodulation. I will have I and Q available on a 4 bits ADC @ 3Gbps.. Do...

Hi all, I'm looking for an architecture dedicated to a Gbps BPSK demodulation. I will have I and Q available on a 4 bits ADC @ 3Gbps.. Do you know what is the best archtiecture in regards to this high data rate ? I though about CORDIC perhaps, but I'm not sure it can handle this data rate... What suggestions do you have to start my research ? Thanks

## MSK Demodulator

inI've seen a number of inquiries about minimum shift keying, it's generation and demodulation. I haven't been able to find anything to...

I've seen a number of inquiries about minimum shift keying, it's generation and demodulation. I haven't been able to find anything to recommend on the web, which is frustrating since I built a MSK receiver for my Master's thesis about 15 years ago. So I've posted my Master's thesis. It goes into some detail about MSK, it's generation and demodulation. It also goes into some detail ab...

## AM SSB demodulation

inHello, I am trying to demodulate an AM SSB (single side band) baseband signal. Are there any standard techniques/papers for AM SSB...

Hello, I am trying to demodulate an AM SSB (single side band) baseband signal. Are there any standard techniques/papers for AM SSB baseband demodulation in the presence of arbitrary phase/frequency offsets? To elaborate my query, let s(t)={m(t)+j*H[m(t)]}*e^(j*2*pi*fc*t) where H[ ] denotes the Hilbert transform, fc denotes the carrier frequency and s(t) is the complex analytic signal be ...

## RTTY (AFSK) demodulation

inHi, has somebody here implemented a RTTY (AFSK) decoder. Any suggestions how to proceed ? I've found some technical abstracts about FSK...

Hi, has somebody here implemented a RTTY (AFSK) decoder. Any suggestions how to proceed ? I've found some technical abstracts about FSK demodulation in the WEB like: - frequency discriminator with IIR resonator - frequency discriminator with FIR bandpass filter - digital PLL Any idea how complex it is to implement one of these methods ? What processor is sufficient for this, does a microc...

## Question on AM demodulation...

inHi all, I am a bit stuck in a demodulation thing. Lets say I have a system that generates an AM signal and wants to detect distorsions of...

Hi all, I am a bit stuck in a demodulation thing. Lets say I have a system that generates an AM signal and wants to detect distorsions of the LF signal after feeding the AM modulated signal through a potentially nonlinear system. This means I have phase locked TX and RX. Lets say I modulate a signal at f0 with sine at f1 with 100% modulation: signal = sin(w0*t) * (0.5 + 0.5 * sin...

## Timing recovery design in PSK demodulation

inHi, We are building a multichannel Q/8PSK demodulation system, we have completed the carrier recovery design, and in the process of designing...

Hi, We are building a multichannel Q/8PSK demodulation system, we have completed the carrier recovery design, and in the process of designing a timing recovery loop to build a stable symbol clock. We have a coarse idea how to do it, but would like to verify the feasibility. The block diagram of our design is 187.5Msps 4R 4R A/D ---------->

## Minimum Bandpass Filter Bandwidth for Binary FSK Demodulation

inI may very well be asking this question prematurely, and I may actually already know the answer but have forgotten it. In either case, please be...

I may very well be asking this question prematurely, and I may actually already know the answer but have forgotten it. In either case, please be kind... In binary FSK demodulation, one normally puts a bandpass filter around each of the mark and space frequencies. How small can this filter be? My thoughts cycle like this: 1) We want the filter to be as small as possible to remove as ...

## I/Q data scaling before AM/FM demodulation

inHi All, I have demodulated two AM files (I/Q) succesfully but for one of the I/Q files which was Gnuradio (USRP) file i had to scale down I and Q...

Hi All, I have demodulated two AM files (I/Q) succesfully but for one of the I/Q files which was Gnuradio (USRP) file i had to scale down I and Q components before demodulation by multiplying by 0.0001 (experimental value) to get the value that can be demodulated and heard on the PC speakers. The values read from file were like these I= 469.00000, Q=-273.0000, I=472.00000, Q=-263.0000,,,,,,,,,,...

## Does decimating after Sampling mean loss of data?

inDear All, I use an AD9371 board and on it the ADC samples the input at 1228 MHz, then the sampled data is decimated by 5 and a downsampling FIR...

Dear All, I use an AD9371 board and on it the ADC samples the input at 1228 MHz, then the sampled data is decimated by 5 and a downsampling FIR filter reduces the output rate to 122.8 MSPS. This is what I have as an input to the FPGA where demodulation occurs. The signal to be demodulated is an 80 MHz wide QPSK modulated one. For ideal demodulation I need a 320 MSPS (x4 symbol rate). My quest...

## CCK demodulation

Hi fellas, I am doing CCK demodulation by 802.11 standard. I have a signal which is a real WLAN packet but i am doing the decoding off line. My...

Hi fellas, I am doing CCK demodulation by 802.11 standard. I have a signal which is a real WLAN packet but i am doing the decoding off line. My original goal is to do this online with a DSP but intially i am saving the packet and doing decoding offline. I know where the CCK modulation starts in a WLAN packet so i starts decoding from that very instant. My operation steps are listed below: 1. ...