Receiver component specifications in PXIe-5644R

[icwon]

Hi,

I have a PXIe-5644R. I would like to ask if there is any documentation available on the specifications of the individual components in the direct-conversion receiver (i.e. LPF, BPF, mixer, attenuator, amplifier) as the PXIe-5644R specification does not contain any information on the individual components.

[santo_13]

If you're asking for instrument board level component specifications - those are not public as it is part of the IP. Moreover, specifications are only meaningful as a whole instrument because you can use it only as an instrument and not piece by piece.

I am interested to know why this information is required or useful to determine the instrument capability which is not already available in the specifications document.

[icwon]

Hi Santosh,

Thank you for your reply. I am interested to know the specifications of the board level components to determine certain parameters to use. For example, without knowing the corner/cut-off frequency of the LPF after the mixer, if I were to have an additional signal received with a desired signal, I would not know at which frequency offset to put the additional signal so that it would be "in-band" or "out-of-band" with the desired signal. Performing a frequency sweep on the additional signal produces different frequency responses at various frequency offsets when analyzing on a FFT which can be hard to debug with limited knowledge on the specifications of the components.

[santo_13]

If you're lucky and have enough connection or leverage with NI, you might be able to get that information using the NI Support channel or your NI Applications Engineer.

Wouldn't the 80MHz bandwidth define the -3dB point of the LPF along with the LO or centre frequency?

[shawn.t]

Have you seen this document? https://www.ni.com/en-us/support/documentation/supplemental/12/the-ni-vector-signal-transceiver-hard...

The block diagrams in the receiver and transmitter sections call out the frequency responses of the different LPFs, but of course, it doesn't describe exactly when one is used versus the other.

The 5644 is pretty simple from an RF perspective. Once you're above 375 MHz, it's a simple direct conversion device. Most of the quality of the RF signal created or received is based on a lot of complex digital filtering. Let me know if the hardware architecture doc helps get you to a solution.

[icwon]

According to the information in the above document, the 80 MHz bandwidth specified is the instantaneous bandwidth of the receiver. In other words, any frequency components within the bandwidth specified will have a frequency response.

So without knowing the specific frequency responses of the components, would this be the best information to choose frequencies to be "in-band" or "out-of-band" of a fixed LO?

[JeffLambert]

This is a really old post, but I feel compelled to respond and answer for reference.

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@icwon wrote:

...any frequency components within the bandwidth specified will have a frequency response.

[...]

would this be the best information to choose frequencies to be "in-band" or "out-of-band" of a fixed LO?

 The answer is NO.

There are a few reasons why, but as stated, you don't need this information.  I think you may be confused, based on your question, there is more information needed.