AM demodulation

Started by luke_ in comp.dsp11 years ago 8 replies

Hi there! I'm finding hard to get information about "switched gain AM demodulation" and how to implement it. Apparently this demodulation ...

Hi there! I'm finding hard to get information about "switched gain AM demodulation" and how to implement it. Apparently this demodulation techique involves synchronization with the signal carrier.. Can anybody provide some hints? Regards, Luke


DIgital V's Analog Demodulation

Started by Barry in comp.dsp14 years ago 1 reply

Hi all, I'm implementing demodulation schemes in digital form and I'm currently trying to establish what the advantages and disadvantages are...

Hi all, I'm implementing demodulation schemes in digital form and I'm currently trying to establish what the advantages and disadvantages are of each domain. I've written down what I think are the most important, and would be interested in hearing if I've covered all the bases and if the information is accurate. Thanks. ***Pros*** * Flexibility – different demodulation scheme


Matlab code needed for SSB demodulation

Started by Rick Lyons in comp.dsp5 months ago 72 replies

Hi Guys, I'm trying to help someone understand the operation of a discrete single-sideband (SSB) demodulation system that is being...

Hi Guys, I'm trying to help someone understand the operation of a discrete single-sideband (SSB) demodulation system that is being proposed to replace an older analog SSB demodulation system. Having not thought about SSB systems for many years, I've been trying to figure out how the "phasing method" of SSB demodulation works. In trying to model this "phasing method" using Matla...


AM demodulation

Started by Steve in comp.dsp14 years ago 20 replies

Having looked through countless websites and books, I've learnt loads, but not what i'm looking for: An algorithm for AM demodulation... ...

Having looked through countless websites and books, I've learnt loads, but not what i'm looking for: An algorithm for AM demodulation... Can anyone help?


CPFSK demodulation and synchronization

Started by gobruins in comp.dsp7 years ago 10 replies

I am trying to build a binary CPFSK demodulator with self synchronization. Modulation index is not fixed. I kind of prefer coherent demodulation,...

I am trying to build a binary CPFSK demodulator with self synchronization. Modulation index is not fixed. I kind of prefer coherent demodulation, but not sure how to do the synchronization. The following is some understandings I have during the literature survey, I appreciate if I can get some comment on my understandings. 1. One type of coherent demodulation I know of is ZCD based and using...


CPFSK demodulation and synchronization

Started by gobruins in comp.dsp7 years ago 1 reply

I am trying to build a binary CPFSK demodulator with self synchronization. Modulation index is not fixed. I kind of prefer coherent demodulation,...

I am trying to build a binary CPFSK demodulator with self synchronization. Modulation index is not fixed. I kind of prefer coherent demodulation, but not sure how to do the synchronization. The following is some understandings I have during the literature survey, I appreciate if I can get some comment on my understandings. 1. One type of coherent demodulation I know of is ZCD based and using...


Repetition Coding and Soft demodulation

Started by Arthur in comp.dsp11 years ago 6 replies

Dear All, Okay, probably this sound a bit silly, but what happens when repetition coding is used and when soft demodulation is used ? Soft...

Dear All, Okay, probably this sound a bit silly, but what happens when repetition coding is used and when soft demodulation is used ? Soft QAM demodulation produces Log Likelihood Ratio (LLR), and should I take average value of the repeated symbols ? Here's the simple view of the receiver Channel --> Soft QAM demodulator--> Repetition Decoding--> De Interleaver--> FEC decoder Any impac


FM demodulation

Started by ma in comp.dsp11 years ago 26 replies

Hello, I want to write a subroutine to implement FM demodulation. The input should be in the format of IQ. How can I do this and where can I...

Hello, I want to write a subroutine to implement FM demodulation. The input should be in the format of IQ. How can I do this and where can I read about the technique and the implementation technique and mathematics behind it? Any help is much appreciated. Regards


FSK Demodulation (Matched Filter) output

Started by engrmasood2002 in comp.dsp3 years ago 2 replies

Hi, All i have some simple questions for HAM Radio/Caller ID FSK demodulation. Studying FSK demodulation using matched filter it is known that...

Hi, All i have some simple questions for HAM Radio/Caller ID FSK demodulation. Studying FSK demodulation using matched filter it is known that the output will be +ve or -ve for mark and space frequency, i am unable to figure out that 1. What will be the output of matched filters when neither 1 (1200 Hz) or 0 (2200 Hz) is transmitted. ? How to know this condition. 2. Will matched filter(non ...


FSK Demodulation (Matched Filter) output

Started by engrmasood2002 in comp.dsp3 years ago 1 reply

Hi, All i have some simple questions for HAM Radio/Caller ID FSK demodulation. Studying FSK demodulation using matched filter it is known that...

Hi, All i have some simple questions for HAM Radio/Caller ID FSK demodulation. Studying FSK demodulation using matched filter it is known that the output will be +ve or -ve for mark and space frequency, i am unable to figure out that 1. What will be the output of matched filters when neither 1 (1200 Hz) or 0 (2200 Hz) is transmitted. ? How to know this condition. 2. Will matched filter(non ...


req help

Started by minu in comp.dsp10 years ago 2 replies

hello i am a final yr project student, and i have to develop c language codes for am and fm demodulation ... i will have to create a dll...

hello i am a final yr project student, and i have to develop c language codes for am and fm demodulation ... i will have to create a dll file which can bbe accessed by labview for display. i could not find any specific directives towards software implementation of am/fm demodulation...can somebody pls help me out?


Digital PLL and FM demodulation

Started by ma in comp.dsp11 years ago 4 replies

Hello, PLL is a good way to do FM demodulation in analogue domain. What about its use in digital domain? Why not to use a digital PLL to do...

Hello, PLL is a good way to do FM demodulation in analogue domain. What about its use in digital domain? Why not to use a digital PLL to do FM demodulation? what is advantages(if any) and disadvantages of this technique? Regards


FM carrier offset and aliasing effects

Started by jacobfenton in comp.dsp7 years ago 5 replies

I am doing digital FM demodulation using the common ATAN2 and first difference method. When the carrier is offset from center, there is...

I am doing digital FM demodulation using the common ATAN2 and first difference method. When the carrier is offset from center, there is a non-linear region that appears and seems to be tied to the FM demodulation sample rate. Without be able to change the FM demodulation sample rate, are there any work arounds from this non-linear region? This non-linear region is just outside my bandwidth of ...


FM demodulation

Started by ksridhar in comp.dsp11 years ago 1 reply

i came to know that FM demodulation can be done through envelope detection. i have implemented the FM demodulation using envelope detection and i...

i came to know that FM demodulation can be done through envelope detection. i have implemented the FM demodulation using envelope detection and i was unable to detect the original signal. i have not implemented the limiter circuit for this. i have passed the FM signal directly to the BPF followed by differentiator and envelope detector how to implement the limiter circuit. please help me. ...


FM rejection for AM demodulation

Started by Jianhong Wang in comp.dsp14 years ago 1 reply

What is the exact meaning of "FM rejection for AM demodulation"? How can I test this parameter if I had an AM receiver? Thanks!

What is the exact meaning of "FM rejection for AM demodulation"? How can I test this parameter if I had an AM receiver? Thanks!


The 'phasing method' of single sideband demodulation

Started by Rick Lyons in comp.dsp5 years ago 22 replies

Hi guys, Some weeks ago I posted a message asking for help in understanding the 'phasing method' of single sideband (SSB)...

Hi guys, Some weeks ago I posted a message asking for help in understanding the 'phasing method' of single sideband (SSB) demodulation. You guys helped me out, and I learned so much that I wrote a blog on that SSB demodulation method. In case anyone's interested, the blog is at: http://www.dsprelated.com/showarticle/176.php See Ya', [-Rick-]


Cramer rao bound on estimating amplitude of the signal using complex demodulation

Started by praveen in comp.dsp14 years ago 4 replies

Hello, I am finding the amplitude of the signal using complex demodulation (quadrature demodulation). I wanted to know maximum accuracy to...

Hello, I am finding the amplitude of the signal using complex demodulation (quadrature demodulation). I wanted to know maximum accuracy to which the amplitude of the one of the frequency contained in phase modulated signal(which is the input) can be estimated.The accuracy to which the amplitude obtained should be 10^-8 (between actual and estimated by this method). So i wanted to know if t...


Sample rate and baud rate issue

Started by in comp.dsp11 years ago 3 replies

I'm working on FSK demodulator with the TMS320C6711 DSK. I've done this demodulation with the method where the signal and its delayed version...

I'm working on FSK demodulator with the TMS320C6711 DSK. I've done this demodulation with the method where the signal and its delayed version are multiplied together and then low-pass filtered. But this demodulation technic is only working if the sample rate is an integer multiple of the baud rate. Does someone know a technic or an algorithm which allow a demodulation of a 300 baud rate signal wit...


Difference in demodulation of DSB-SC and SSB-SC

Started by 10023101 in comp.dsp11 years ago 8 replies

hey guys, just wanted to know if any1 could please shred sum light on wat would the differnce in demodulation schemes of double side band...

hey guys, just wanted to know if any1 could please shred sum light on wat would the differnce in demodulation schemes of double side band suppressed carrier and single side band suppressed carrier. This is what i done with matlab coding for modulation and demodulation. 1. DSB-SC: - Modulation: (message signal 500hz) multiply by (carrier frequency 7000hz) ie: cos (2 pi 500 t) x cos (2pi700...


sin and cos signal generation for IQ demodulation in dsp

Started by praveen in comp.dsp14 years ago 4 replies

Hello, I am doing IQ demodulation in DSP. Only one reference signal(sin) fo is coming as reference. I have generate 2fo,4fo from it and...

Hello, I am doing IQ demodulation in DSP. Only one reference signal(sin) fo is coming as reference. I have generate 2fo,4fo from it and also generate orthogonal signal of each of it for IQ demodulation. All these frequency should be phase looked with the reference signal.My question is how to generate these.Any special techniques for generation. Any reference or suggestion will be great. ...