How to measure mixer conversion loss of a mixer with a 2 port ENA

[PauliMatrix]

Hi everyone,

I have a mixer (double balanced) from which I want to measure the conversion loss and other relevant parameters. I have a 2 port ENA, which does not have the wizard help that some ENAs have to measure a mixer. Could anyone iluminate me on how to do this measurement? I know frequency offset is involved, but I seem to don't be able to properly measure this.

Thank you!

 

[BigBoss]

Why you have some doubts about "Frequency Offset" option ?? I used this method years ago to measure a mixer and it gave me a good result.

 

[PauliMatrix]

Why you have some doubts about "Frequency Offset" option ?? I used this method years ago to measure a mixer and it gave me a good result.

Hi,

It is not that I don't trust it, it's that I don't know how to use it. (It would be great if you could ilustrate me!)

Thanks!

 

[BigBoss]

Some modern VNAs have this Optional Feature. I cannot illustrate here but you can find lot of information about it for instance Keysight's website. Simply you drive the Mixer by LO and the difference (or sum) IF frequency is received by VNA and you see the Gain directly. Here, Off-set means that VNA while Port1 is sweeping the driven frequency, Port2 sweeps LO+RFin frequency so there is an off-set.
In fact, there is a wizard for this purpose and all you need is to enter the required values. VNA computes the rest.

 

[PauliMatrix]

Some modern VNAs have this Optional Feature. I cannot illustrate here but you can find lot of information about it for instance Keysight's website. Simply you drive the Mixer by LO and the difference (or sum) IF frequency is received by VNA and you see the Gain directly. Here, Off-set means that VNA while Port1 is sweeping the driven frequency, Port2 sweeps LO+RFin frequency so there is an off-set.
In fact, there is a wizard for this purpose and all you need is to enter the required values. VNA computes the rest.

Yes, I know about the wizard, but my VNA doesn't have it. That's why I need to do everything manually.

Thanks!

 

[vfone]

If you don't have LO source available in your VNA for mixer measurements, you can use two signal generators (RF and LO) and a spectrum analyzer at IF port.
The difference between RF and IF levels is the mixer conversion loss (or gain if is active). You can play with the LO level, to see the influence on the mixer conversion loss or gain.

 

[PauliMatrix]

If you don't have LO source available in your VNA for mixer measurements, you can use two signal generators (RF and LO) and a spectrum analyzer at IF port.
The difference between RF and IF levels is the mixer conversion loss (or gain if is active). You can play with the LO level, to see the influence on the mixer conversion loss or gain.

Is there an obvious way of doing this with a VNA, coupling/uncoupling receivers and detectors?

 

[FvM]

The VNA must provide a wideband detector mode to support mixer conversion loss measurements. You also need an additional RF generator and optionally a band pass filter to extract RF-LO or RF+LO from the mixer output signal.