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FSK modulated wave file

Hey guys, Though my problem is do a FSK modulation os an ascii string and send it to telephone between "init ring" and "full ring" , I don't know how to test. Is there a software FSK demodulator free somewhere? Can I get some standard FSK modulated file to test the decoder? So that I am test my c...

PSK instead FSK?

Hi, I just started up some reading on Digital Communications. I need some information about PSK vs FSK for use in DSP. Can anyone explain in few words the advantages of using PSK instead FSK? Will appreciate any help in this regard. Thanks ...

xr2211 & non coherent fsk demodulation

Hello, I am using the XR 2211 to demodulate a non coherent fsk signal. It works but I would like to know how to evaluate the theoritical BER performance of this demodulation. But all the non coherent fsk receivers that are mentionned on the web dont use a pll ... any idea ? thank you very m...

Is there a software FSK encoder API for PC using no addtl hardware?

Hi All, We need an API module to allow us to send data using the FSK (Frequency Shift Keying) modulation. This module is to run on a PC and may use no additional hardware except for the built in sound card. The module will allow us to convert ASCII characters to their FSK sound and play tha...

software for generating FSK modulated signals

hi I have to generate signals with data encoded in them using FSK, 1300Hz for mark and 2100Hz for space with a baud rate of 1200. i dont have an FSK modulator so is there any software that could do this over voice modem ? i dont have any backgound of DSP so i would really be thankful for yo...

Is frequency multipliers suitable for boradband FSK?

there are many applications use frequency multipliers to improve the deviation of narrowband FSK . i wonder is it suitable for boradband FSK? For example,the input signal should be 4FSK,and the frequencys is 67MHz/69MHz/71MHz/73MHz,the symbol rate is 10M . ...

Who made the comment about modems and FSK signals?

I think some respondant named 'v' made a remark in response to a post I made last week regarding FSK decoding and filtering, but the post has been removed. The remark concerned the special processes that have to be done detecting FSK tones that are very short in the sense that the number of per...

Few taps Filters for FSK?

Does anyone have any suggestions for an IIR or FIR band pass filter that will isolate the two tones of an FSK signal which an integrate and dump scheme can then be applied to? I need to minimize the delay since this FSK signal comes from scanned radio frequencies. I need to detect the signal f...

Detecting FSK on a power fft pk hold spectrum

Found this board, and hopefully someone can give me a helping hand. Background: I'm using labview with a DAQ. It's acquiring a signal and I take a power fft with peak hold averaging on. In this spectrum, there are atmospheric noise, some other signals with large BW about 250 hz, and signals that...

Fax/modem detection

Hello, I m implementing fax/modem detection. So far it is based on CNG and CED tones. Goertzel's algorithm is used for tones detections and seems to work fine. However I would like to increase reliability, specialy for cases when such tones are not present or missed. Idea is to do it by detecting...

FSK bandwidth

What is the estimated bandwidth using Carson's rule when your separation is 19.8 kHz, the baud rate 19.2 kBaud/s modulation is FSK, NRZ line coding and the crystal tolerance is negligible? Thanks ...

FSK Demodulation (help urgently needed)

Hi I am trying to Extract Caller ID from FSK v.23 Encoded CLI Packet which has been stored in audio format in pc. To demdulate FSK i am using two Bandpass Filters centered at Mark and Space Frequency. According to FSK V.23 1300 hz is frequency for mark(1) 2100 hz is frequency for spcae(0) 120...

FSK and timing recovery

Hi, I'm trying to gain an understanding of how to do timing recovery or symbol synchronization in a digital radio receiver but I need something clarified. The methods I have found information on (Mueller & Mueller, Early-late, Gardner etc) seem to be intended for linear modulation schemes but wha...

FSK Versus OOK Demodulation

With the right filtering, an FSK signal can be viewed as two complementary OOK (on-off keyed) signals. Is the optimal FSK demodulator more optimal, less optimal, or equivalent to two optimal OOK demodulators with their outputs combined? -- Randy Yates % "Watching all the d...

Multicarrier modulation scheme vs FSK

Hey, What is the difference between multicarrier modulation and FSK (Frequency Shift Keying)? Can OFDM considered to be a hybrid of the two? Thanks TD ...

clock recovery

hi, I have implemented a binary FSK modem(V.21). but i have a question: how can i implement clock recovery for fsk demodulator? does any reference exist for this subject? please help me. ...

FSK demodulator code?

I'm looking for code, either in ANSI C or assembly for the ARM7TDMI, that'll demodulate 1200 baud FSK, in particular 1200 baud Bell 202 keying like that found in caller ID systems. Any suggestions? Thanks, Scott ...

GMDSS/DSC FSK Modulation: Continuous-Phase or Not?

Hello, I'm looking at demodulating a GMDSS/DSC (Digital Selective-Calling) 100 baud FSK (1700 Hz center, +/- 85 Hz) signal (per ITU-R M.493-12). The spec says nothing about whether it's continuous-phase FSK or not. I've found on the net that DSC is similar to SITOR-B, and further that SITOR...

general fsk question

I am trying to understand fsk demodulation in general. Is there an industry standard set of specific demod schemes or just classes of particular methods (i.e. matched filter, correlation, coherent vs non-coherent) that are invoked on a project by project basis? ...

Definition of modulation index for shaped FSK

I have a pretty elementary question. For an unshaped, 2-FSK signal, the modulation index h is defined as the ratio of the difference between the two tone frequencies to the symbol rate. For shaped 2-FSK, how is h usually defined? I can think of a few possibilities: (1) Base it on the pe...

Re: FSK Correlation Demodulator

Vale_a_pena wrote: > I can try to help you Opamp. > > Even without money :) > > When you mix two signals: y1*y2 with y1 FSK signal and y2 a > sinusoid > > You obtain a result varying in time (y1*y2)(t) > > > Correlation is the integral during a period of T o...

PC FSK decoding - stuck beginner!

Hi, I'm urgently trying to get my head around methods for decoding an FSK encoded signal on my PC. I have a .wav file of the transmitted data, and I want to get the data out. I'm doing my work in Matlab/Simulink for now for simplicity. So far I've tried: - Goertzel algorithm as used for dtmf -...

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...

fsk demodulation

I am a novice in DSP.I am trying to demodulate a FSK signal wherein the mark and space frequencies are 16MHz and 24MHz respectively.I am thinking of using delay and multiply method.Can this be implemented using an ADSP-2181?More specifically will the DSP be able to handle the high throughput involve...

FSK Demodulator

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 a...

FSK encoding: alternatives to Manchester and NRZ

Hi all, I noticed a lot of FM related questions this month, so here is another one... I am transmitting FSK using a MICRF505 transceiver chip. The FSK modulator in this chip requires a bit encoding scheme to reduce the DC content of the bit stream to a manageable level. I am struggling with ...

Coherent FSK

A colleague and I are trying to understand the performance limits that apply to coherent detection of continuous phase FSK in AWGN. As I understand it, the familiar textbook formula for coherent FSK BER is derived for the case of square one-bit pulses and tones that are orthogonal over one bit t...

Re: FSK mod and demod

Gunstinger wrote: > Hello I'm stuck with a little problem here in MatLab. What I need to do is > input a string of text, convert it to binary, and then use FSK to mod it > together, then demod and and filter it out and convert it back to text > again. The first part is easy, the input of tex...

Question about Continuous Phase FSK

I am trying to understand what is meant by continuous phase FSK. Right now I am of the opinion that it means that a very quick change in frequency can take place as long as there is no discontinuity in the time waveform when the frequency change takes place. Is this a correct interpretation? ...

What is the maximum bits-per-symbol possible using FSK on telephone devices?

Hi: What is the maximum amount of bits-per-symbol of FSK possible using a telephone system [including the phone lines and any devices from start to finish of the phone's signal chain]? Thanks, Green Xenon ...

Goertzel and FSK

Hi all. Adapting Goertzel algorithm for FSK in a system with a preset sampling rate, tones and baud rate does not always result in ideal parameters. Let me try to explain what I mean: For example, consider a case with Fs=9600, tones 1650 and 1850 Hz, and baud 300. That's N=32 samples per symbo...

Anyone have a Good filter for FSK with short delay

I need to find a bandpass filter with as few taps as possible to apply to an HF radio FSK signal. The reason is that the radio is scanned and the more taps, the longer it takes before the signal can be recognized which slows down the possible scan rate. Can anyone give me any references or id...

Re: Detectiong CW

In article , "John E. Hadstate" wrote: > What's the slickest way of turning an I/Q data stream, tuned > to baseband, into audible Morse Code with user-selectable > pitch using strictly digital signal processing? > > > John, The CW pitch-shifting feature is in the Timewave DSP-5...

FSK - sample rate and bit depth

I'm working on a couple of demodulators - one for 1200 baud AFSK (and possibly other bitrates) and one for 9600 baud baseband FSK - and I've got some questions. I'm using an ARM7TDMI chip, so I'm rather CPU constrained. An issue I'm having trouble with is that the CODEC I'm considering off...

Decoding FSK

A Bell 202T modem uses FSK modulation (1200HZ, 2200HZ) and send data at up to 1800 bits per second. I need to replace an "analog" version of this with a digital version, sampling the phone line with an A/D and "decoding" the 1's and 0's in firmware (ARM C). My question is how.. The modu...

FSK demodulation

Hello all, I am involved in the development of an underwater modem. Right now I am dealing with the simulation stage with simulink. The modulation scheme I am using is a non-coherent FSK. The carrier frequencies are 20kHz and 22kHz. At the demodulator part, I have designed a matched filters...

FSK modulation and clean FFT

Hi, I'm looking at FSK modulation in matlab, using my own modulator as I don't have the matlab comms toolbox. In the time domain, the signal looks fine, but in the frequency domain, it just doesn't seem to work, I get lots of other garbage in the spectrum. I'm hoping someone can see an error ...

Receiving symbols using non-coherent M-FSK

Hi There, How does the demodulator of a non-coherent M-FSK system correctly time the "reading" of the symbols? In the book on Digital Comms by Proakis, it is mentioned that a bank of 2M correlators can be used. In the book there is also a model for non-coherent M-FSK in an AWGN environment. ...

ping: Jim Thompson

Jim, I was perusing your website and happened upon your patent regarding demodulating of FSK. Is this the currently easiest/best way to decode FSK? Or would I be better off doing with SW and microcontroller? I was thinking that a comparator with hysteresis to minimize noise could be used to...

Robust FSK demodulator ?

Dear all, We are looking for a robust FSK demodulator and framer solution for an SDR application (decoding of simultaneous narrow channels at some kbps each from a wider baseband stream) : channel filtering, center frequency tracking, demodulation, bit-level timing recovery, synchronisation...