Forums › General Discussions › Scalar analysis – why resolution is limited to 1KHz?
- This topic has 2 replies, 3 voices, and was last updated 8 years, 2 months ago by Justin Crooks.
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Ivan IonovParticipant- This topic was modified 8 years, 4 months ago by Ivan Ionov.
Hello,
I’m trying to make some simple analysis of quartz resonator response (30MHz for example). I know for sure, the tracking generator can output frequency with 10Hz step around the desired frequency, but scalar analysis can’t make steps less than 1KHz.
Compare 2 pictures, one with scalar analysis (I request 500points in 50KHz range, instead I get only 50points), second with the same tracking gen doing sweep with external software.
The resolution is much better in second variant, so I see the hardware can do much better resolution, but Spike have some strange limitation.
May be in 2.2-4.4GHz range the TG44 can have 1KHz resolution and the limitation is correct there, but in lower ranges the scalar analysis can be significantly improved.
Regards, Ivan
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AndrewModeratorHi Ivan,
There are some hardware/software limitations that limit the step size to 1kHz with the TG/BB combo. I apologize for the inconvenience.
Regards,
A.J.
Justin CrooksModeratorIvan,
High Q devices require a long settling time, often tens of milliseconds, before an accurate measurement can be taken. This is one reason we limit the step to 1 kHz–any finer resolution would take exponentially longer to measure.
In Spike, you can accomplish a high Q insertion loss measurement using a MAX HOLD trace and the TG CW utility, manually stepping across the frequencies of interest. Your “external” sweep with max hold is a good approach to this, and essentially automates this process.
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