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improve the sampling rate of PXI 5600+5620, bandwidth of 5610+5421.

We have a signal generator (NI PXI 5610+5421) and a vector signal analyzer (NI PXI 5600+5620).

 

Now the highest bandwidth of the signal generator is 10MHz, and the highest sampling rate of the vector signal analyzer is 60MHz. How can we get higher bandwidth than 10MHz and higher sampling rate than 60MHz?

 

Thanks a lot. 

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Message 1 of 13
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Hi WLPS,

All the information you are looking is on the help for each one of those devices. For example the 5610 and the 5421 is what is called a 5670, the help for this device is located at: “"C:\Program Files\IVI Foundation\IVI\Drivers\niRFSG\Documentation\RFSG.chm"” and there should also be a shortcut on you start menu programs. We state on our help that: “100 mega samples per second (MS/s)— default. This setting provides the best possible anti-aliasing performance, up to 20 MHz of instantaneous bandwidth, and the best time-domain resolution of the signal. This setting is recommended for most applications. 50 MS/s — this setting has several specific situations in which it is useful. These situations are discussed in more detail in the following section”.

Now with the 5660 a.k.a. 5600 + 5620 the 5620 ADC can’t go faster that 60 MHz

Why do you need an higher generation bandwidth and a faster sampling rate? What is your application?

Depending on what you want to accomplish one of your solution might be upgrating to our new 6.6 Ghz paltaform, 6.6 GHz RF Instrumentation for PXI

I hope thsi helps
Jaime Hoffiz
National Instruments
Product Expert
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Message 2 of 13
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Hi Jaime,

 

First, thank you for your fast reply.

 

We want to use the transmitter and vector analyzer (receiver) to measure wireless channel delay profile. So high bandwidth transmitted signal and high speed sampling receiver are needed.

As you said, with 5670, we can get transmitted signal bandwidth up to 20MHz; and with 5660, we cannot go higher than 60MS/s, right?

 

Thank you again,

WLPS 

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Message 3 of 13
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Yes, that is correct.
Jaime Hoffiz
National Instruments
Product Expert
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Message 4 of 13
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Hi Jaime,

 

Got your answer on the sampling rate and band width.

 

We have another problem, power.

 

When we use the system (vectro signal generator and analyzer) to measure outdoor channel, the transmitted power of the signal generator and the receiver sensitivity of the vector signal analyzer are not high enough. We have bought a PXI 5690 to get more gain (about 50dB), but in outdoor, we still cannot catch the reflected signals (small power). Do you have any idea to catch the reflected signals with small power? Or does NI have any other card to enhance the receiver performance?

 

Thanks a lot,

WLPS   

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Message 5 of 13
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Hi WLPS,

How low is you power? I know this might be hard to answer but maybe a rough estimate of what you are expecting to receive. Can you read with a smaller span and a smaller RBW to see if your noise floor can drop lower than your signal?. Lowering the RBW and SPAN might not be good for your PDP application but it might give you the chance to see how low is your signal. (Understanding RF & Microwave Specifications - Part I, http://zone.ni.com/devzone/cda/tut/p/id/4446) and (How can I Achieve the Noise Density Specification Mentioned in the Specifications Document of the NI 5660?, http://digital.ni.com/public.nsf/allkb/C380775A3DA8639F86256FF0007205C8)

Besides that and generating at the maximum power of the 5670 I don’t think there is much we can do. Some ideasr are: one you might be able to get a third party amplifier to be used with the 5670; two another LNA (not the 5690) with you acquisition side, just make sure the noise figure is still good for your application and thirs a directional antenna, although I think the antenna solution defeats the purpose of a power profile delay.  

A good resource about antennas is: http://etd.lib.fsu.edu/theses/available/etd-04102004-143656/unrestricted/Chapter2.pdf/
Jaime Hoffiz
National Instruments
Product Expert
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Message 6 of 13
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Hi Jaime,

 

Thank you very much!

 

We will measure the signal level when we have a chance. There are too much snow outdoor now.

 

And we will consider your suggestions!

 

Best regard,

WLPS 

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Message 7 of 13
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Hi Jaime,

 

I just read the data sheets of the NI PXIe-5663 and 5673. But I did not find the sampling rate of the 5663, its instantaneous bandwidth is 50MHz, does that mean its sampling rate is 100MHz?

 

If we upgrade to the 6.6 GHz platfor, can we get 50MHz bandwidth signal transmitted at the NI PXIe-5673, and at NI PXIe-5663, we can get a 100MSps, and store the data at hard drive or on board memory?

 

Best regards,

WLPS

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Message 8 of 13
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Hi WLPS,

Your are in the right track but some things are not right on your statements.
Let’s start with the 5663, you are correct by saying that it has a 50 MHz instantaneous
bandwidth but this does not relate to sampling rate, my guess is that you are following
Nyquist theorem for stating the the sampling rate at twice the bandwidth but when
you are dealing with bandpass signals the theorem changes a little bit. This
wiki article helped me refresh all those concepts I have not seen for a
while: http://en.wikipedia.org/wiki/Sampling_(signal_processing). The bandwidth, even
if you can sample at 1 GHz will still be limited by circuitry.

Be aware that 50 MHz of bandwidth is only achievable
in the frequency range of 330 MHz and 6.6 GHz as you can see in our manual,
PXIe-5663 Specifications
, page 3.

If I’m not mistaken you are trying to do a power profile delay and this measurement
can be done by generating a modulated signal and correlating the received one
to a known pattern or, what I think you want to do, generating a pulse and
modeling your system with an impulse response analysis.

The 6.6 GHz platform might be a solution for you if you are looking for a wider
bandwidth but due to the complexity of the application I would suggest
handling this issue over the phone, if possible.  

I would like to point you here and request phone support, for sure,
one of my co-workers or I would defenetly get the call since we are the team
that support that hardware. Also, if you are OK with it,
we can later on post your results and your code to this discussion forum,
making them available to the public and helping other customer's similar questions. 
Jaime Hoffiz
National Instruments
Product Expert
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Message 9 of 13
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hello I need help  
I am student of the Universidad de Sonora, I am working with the PXI 5600 + 5620 RF signal analizer
But I have a problem, when introducing the ni5660 initialize.vi  appears a window, and ask me to look the name of the VI "MT get attributes" among others
For all the ni5660 palette occurs the same.

 

i hoop to answer me soon

 

thanks for your help.

 

I'm Alán González.

I'm studing Ing. Electronics in 9th semester.  

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Message 10 of 13
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