signal

[madd]

Hi

Tnx again i have two points now

1. i have used Timing and Transition VI but same is the issue as 2500HZ  frequecncy signal is detected as 2387.23Hz signal.i am attaching here a qpsk 2500HZ signal wave file kindly look into this and also i am attaching the way i am using to read this wave file in Labview.

let's be simple

2. I am only intersted in detecting the right frequency in labview. u have a signal i have informed u about frequency(carrier).and atached the blocks i am using in matlab.kindlly ammend my ".vi " to read right frequency. I am not interested in FFT of the signal. i just want to detect the frequency generated in matlab. cus i want to generate a signal of same frequency that is detected frequency

Regards

Madd

[Eli_S]

Hi,

Yes that is very strange. Let me investigate this issue further and I will let you know as soon as I have some more infromation.

[Eli_S]

Hi,

I have investigated your issue and I what I am almost certain that is happening is that the signal you are generating is not continuous. I looked at the scope picture you posted and there are gaps and extra peaks in certain parts of the signal. I have attached this picutre again pointing out some of the irregularities. I would recommend trying to generate a more continuous signal.

[Eli_S]

Sorry, forgot the attachment!

[madd]

Tnx

For ur Kind investigations but u have only answered my first part second one i mentiond was

I am only intersted in detecting the right frequency in labview. u have a signal i have informed u about frequency(carrier).and atached the blocks i am using in matlab.kindlly ammend my ".vi " to read right frequency. I am not interested in FFT of the signal. i just want to detect the frequency generated in matlab. cus i want to generate a signal of same frequency that is detected frequency.

Let's make life simpler. i am receiving a QPSK signal i want to multiply it with a Local Ossilator signal to shift it to base band. but i need to know the frequency of coming signal so that Local Ossilator will generate same frequency.(u know Carrier recovery)

offcourse i know my signal is not continous since it is QPSK where threre are shifts in phase signal remain's no more continous.but what is the solution.

Regards

 Madd

[Brian_T]

madd,

I added some new measurement analysis VI's that provide a much more accurate response that you were seeing.  A few of them are not available in the LabVIEW Base package, so I also showed a way to use the Tone Measurements Express VI to get the response.  There's an option within this Express VI that allows you to "Search for Specific Frequency."  You can use this if you what the frequency should roughly be.  Let me know if this works for you application. 

Brian T

[madd]

NOP'S

i will try something else.whatever TNX for ur guidence.let me think of another question

Regards

Madd