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PXIe-4464 or PCI-4462

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Hello

 

We are looking to purchase an ADC for voltage flicker noise measurement with the following specifications:

1) 24-bit resolution

2) Low intrinsic noise 

3) AC input coupling 

4) Sampling rate>50k S/s

5) Dynamic input 

The PXIe-4464 unit sounds perfect for our purpose. But due to budgetary constraints(PXI units require a chassis and a controller), we will prefer if a more affordable option exists(which can be mounted directly inside a desktop's PCI slot).

 

The user manual of PXIe-4464 and PCI-4462 have almost similar specs, in particular, both of them have the same intrinsic input noise, sampling rate, resolution and 6 gain input. 

 

I have two concerns regarding picking PCI-4462 :

 

1.  Can it be bought as a standalone unit, or does it require any external controller or chassis?

 

2.  The -3dB cutoff frequency for PXIe-4464 is 0.72 Hz, which is an order of magnitude smaller than it is for PCI-4462(3.4 Hz). Since we are primarily interested in low-frequency signals, I understand that it will affect the signal flatness on low-frequency end. Moreover, this link states that "Using AC coupling results in a drop in the low-frequency response of the AI circuitry. The AC coupling circuitry is usually characterized by a 3 dB cut-off frequency. However, the roll-off from the high-pass filter can have a measurable effect even at frequencies several times greater than the 3 dB point."

 

Keeping these two things in mind, which ADC would be more suitable? Please recommend an alternative unit if available. 

 

Thanks 

 

 

 

 

 

 

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Accepted by topic author ft_louie

For #1, since it is a PCI card, you can just buy the card and plug into PC's PCI slot and no additional hardware would be required (external cables as needed).

 

For #2, since you're looking to measure low frequencies the PXI 4464 seems to be a better option (with the caveat of PXI Chassis investment).

 

Alternatively, you could also look into C Series Sound and Vibration modules along with a USB cDAQ
https://www.ni.com/en-us/shop/hardware/products/c-series-sound-and-vibration-input-module.html

cDAQ-9171 is a low-cost single-slot USB chassis for cDAQ

Other chassis options https://www.ni.com/en-us/shop/hardware/products/compactdaq-chassis.html

 

Santhosh
Soliton Technologies

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