How to convert an anlog signal having frequency range 40MHZ~800MHZ, to digital

I have an analog signal with frequency range 40MHZ~800MHZ. This is to be converted to Digital Signal and will be given to LPT port of the computer. From there this will be captured and compared with a pre-stored data. Please guide me to do this.

Hello;
To digitize an analog signal and have a good and accurate representation of the signal, the sampling frequency must be at least 8 times the highest frequency of the analog signal.That means, that you would need to digitize at 5 GHz frequency.
NI doesn't have a product that allows that high speed.
Regards
Filipe A.
Applications Engineer
National Instruments

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How to convert a analog signal to digital signal

Hello,
How to convert an analog signal into digital signal such that every sample of analog signal corresponding to 1.2V will be represented as '1' in digital signal and other samples of analog signal(that are not 1.2v) will be represented(converted) as '0' in digital signal.
And how to display both wavefroms or signals in graph indicators.
Thanks.
Solved!
Go to Solution.

If you have 1000 samples, and you want to convert to digital, you are going to get 1000 digital values. Attached is what I mean.
Unofficial Forum Rules and Guidelines - Hooovahh - LabVIEW Overlord
If 10 out of 10 experts in any field say something is bad, you should probably take their opinion seriously.
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Analog_to_Digital Hooovahh Edit.vi ‏52 KB

How to convert a waveform signal into array of complex numbers

How to convert a waveform signal into array of complex numbers.

Hi Chaks,
try this:
(Get Waveform components, convert to complex DBL)
Message Edited by GerdW on 01-28-2008 09:23 AM
Best regards,
GerdW
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How to convert a baseband signal with bandwidth 20MHz to an RF signal with center frequency 2.4GHz and the same bandwidth 20MHz

Hi,
I was wondering how to convert a complex baseband signal with bandwidth 20MHz to an RF signal with center frequency 2.4GHz and the same bandwidth 20MHz in simulation. I tried
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I should add that you can multiply your baseband signal with two carrier signals that are shifted by 90° and then add or subtract the result to obtain upper or lower sideband only. You can try to search about IQ moduilators/demodulators to learn more.
Cheers
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Go to Solution.
Attachments:
convert XY Graph to Signal In.vi ‏25 KB

Its ok folks, i have found a solution. See attached FYI.
Attachments:
convert XY Graph to Signal In.vi ‏43 KB

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How can i design square signal which having a positive and negative values equal to each other and separated from each other by controlled time or distance

How can i design square signal which having a positive and negative values equal to each other and separated from each other by controlled time or distance, As it is shown in the figure below. and enter this signal in a daq.
Solved!
Go to Solution.

By the time you spend for the nice diadram you might have done the vi
Your DAQ like to have a waveform (array of values and dt ak 1/samplerate)
If you set the samplerate you know the array length , create a array of zeros, and set the values of both amplitudes ...
Since I don't want to wire others homework here are some pictures
And there are some drawbacks is room for improvement in my solution, just think of rounding errors ... and what might happen if the arrays get bigger ....
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How DAQmx Create Channel for Accelerometer will convert the voltaage signal into g

HI all,
I want to know about DAQmx Create Channel for Accelerometer hoe it will do the convertion any one reply me
Regards,
Santhosh M

Most of the accelerometers that i have used till now are ICP devices.
They need about 5mA current to power them selves up. Other wise they give inaccurate output.
I guess you are measuring a raw time domain vibration signal.So you just need to
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How do i generate any signal for very small frequency

Hi,
I want to generate a sinusoidal waveform at f=0.01 Hz, which is a quasi-steady regime in pipe flow and is very important to generate such a small frequency-flow for me. However, when I enter the value of 0.01 to the related frequency blank and run the program, it always fails and give the same error which can be seen in the attachment "f=0.01.jpeg". When I go through the place where the error generates, I can not see any problem???
My other problem is that: For frequency range between f=0.05 Hz and f=0.1 Hz, I can generate the waveform, but the vi always detect the same frequency as 0.1 Hz. For all entering frequency values of 0.05, 0.06, 0.07 Hz,the program detects the same frequency of 0.1 Hz. But, after f=0.1 Hz, the program detect the correct frequency which is entered. i.e.,if I enter 1 Hz, the program detect 1 Hz after executation of the program or for f=10 Hz, it can detect the same frequency of 10 Hz.
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Unsteady Pipe Flow AnalysisDEMO.zip ‏50 KB
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Hi Kyle A.,
How can I eliminate the small vibration/perturbation on the sinusoidal signal as shown in the jpg file that I now attached? Could you please help me? I think it is due to electrical noise (power line noise of 60 Hz). Thank you again.
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Hi guys,
I am new in Labview. I use Labview to accquire the output data from a measurement circuit with RS232 bus. The result needs some mathematical operation to have a meaningful number. After this operation the result is a scalar variable that is changing as new data read from my circuit. I want to see the power spectrum of this signal so tried to use FFT block (Labview 6.1, signal processing->frequency domain->real fft / power spectrum). However because the fft block needs 1-D array type of data as input, I can not just connect my result to the fft block. The error it gives me is:
These cannot be wired together because their data types (numeric,
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The type of the source is double [64-bit real (~15 digit precision)].
The type of the sink is 1-D array of double [64-bit real (~15 digit precision)].
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I pass the data directly through a For-loop, the result is a 1-D array with all the members having the same value as the input value(my calculated result). Then next time a new result come in, all of the members of that array changes to the new value.
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Hi nano,
"So I interpret that as putting the for loop (the subVI) in another for loop?" - Yes, correct.
See example! (Also on better using LV primitives.)
Where is this "vsource control block"?
Message Edited by GerdW on 03-02-2009 11:24 PM
Best regards,
GerdW
CLAD, using 2009SP1 + LV2011SP1 + LV2014SP1 on WinXP+Win7+cRIO
Kudos are welcome
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How to convert pulses into RPM

I am using a counter to count the pulses given from a hall sensor to detect the speed of a motor. I can see the pulses on the graph and I have the operation running in a while loop but I am having issues with setting up a fixed time for the counter to run. I am using a USB 1208LS DAQ which requires Universal Library and I don't know how to convert the pulses that I get into a frequency or RPM's.
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I am not very familiar with the hardware you have or the Universal Library. It seems from the spec page for the device however that it does not have any counters on it. So is this being read in as a digital channel or an analog channel, because I did not see any specifications on the sampling rate of the digital channels?
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How to output a TTL signal from a sine wave [Please Help]?

Hi evryone!
I am a bit lost...
We make the acquisition of voltage (sine wave, 3Hz) which I simulated by a waveform generation in my VI. We want to convert this analog signal to a TTL and output it with a multifunction DAQ (6230).
I only used Analog to Digital.vi and DAQmx write.vi and I can't get it to work... I get a TTL which is not 3Hz and only If I input a frequency like 3.07 and not 3.00 !!
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ADC.vi ‏26 KB

In your vi, you don't have DAQmx Timing setup. I don't know what the default value is. But the timing determines how fast the DAQ will output values. If not set correctly, you may see slight change in the output frequency. Another thing is that the timing is based on a master clock, like 50MHz. The clock gets divided down until it gets near the desired setting. So it may not be able to achieve 3KHz exactly. If you are getting 3.07KHz, this may be why. I don't know if there is anything you can do about it. Try using the timing vi and setting different sample rates.
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How to convert waveform data to IQ data?

I am currently doing a project which requires me to acquire baseband signals (downconverted from RF signals) from typical PC soundcards and demodulate them (both AM and FM). I am considering to use existing example called "Sound Input Read.vi" to acquire the signal from the soundcard and I have Modulation Toolkit to help me perfrom demodulation. However the datatype of the output signal of Sound Input Read.vi is an array of waveforms, and if I want to use "MT Demodulate AM.vi" or "MT Demodulate FM.vi" provided by the Modulation Toolkit, I will have to convert the baseband signal that is stored as an array of waveforms to a more complicated form which includes the complex data array (I/Q data).I do not know how to achieve this conversion. And all I have is simply baseband signals from the soundcard.
In the file named "Direct-Conversion Receiver.vi", I need some means of conversion and demodulation in the case structure, and that is what I am struggling with. Thank you.
Attachments:
Magic Radio.lvproj ‏22 KB
Direct-Conversion Receiver.vi ‏74 KB

Hello liuzhao_hh,
The data you are feeding into the Demodulate AM/FM is in the incorrect format. The cluster should contain a value for:
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Dt: dt specifies the time interval between data points in the acquired signal.
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I/Q data is an alternative method of describing the magnitude and phase data of a signal.
A sinusoidal wave can be written in polar coordinate form as shown in the following equation:
f(t) = Acos(2ft + φ)
where:
A is the amplitude
2πf is the frequency
φ is the phase
A sinusoidal wave can also be represented in a complex Cartesian coordinate system by its real and complex components such that the in-phase (I) component can be written as
I(t) = Acos(φ)cos(2πft)
and the quadrature (Q) component can be written as
Q(t) = Asin(φ)sin(2πft)
You can find the functions for dealing with imaginary, real, conversions etc located in the numeric pallet, there are also further math functions available in the mathematics pallet, see image below:
Regards
Andrew George @ NI UK

How to convert an anlog signal having frequency range 40MHZ~800MHZ, to digital

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