# Phase & Magnitude vs Frequency curves for 430 KHz preamplifier

Hello all

We have developed a 430 KHz preamplifier using AD600 IC with 50 KHz bandwidth having input voltage range from 0.25uv to 3mv. We need some instrument with the help of which we can plot Phase vs frequency curve and Maginitude vs frequency curve of this preamplifier. We have Standford spectrum Analyzer which have option for both these plots but unfortunately it operates only upto 100 KHz.

Can any one kindly suggest some suitable instruments with the help of which we can automatically plot both these curves in this frequency range i.e. above 90 KHz to say 500KHz.

Thanks & Best Regards

Nauman

• Hi Nauman,

For this kind of measurements, we usually use a network analyzer to plot the Gain Bandwidth and Phase Margin. In our lab, we have the Agilent E5061B which can support up to 3 GHz.  We are using this since we have a variety of products that needs to be evaluated that ranging from few hertz to Gigahertz. Though the equipement specs might be overkill for your measurements and you may want to look for a network analyzer that has sufficient bandwidth for your setup.

Let me know if you need anything else.

Best regards,

Emman

• Dear Emman

Thanks very much for reply. I just need to clarify my own concepts that how
for example E5061B  will measure Phase and Gain vs Frequency curves.

1. First the equipment will transmit a single tonal or frequency signal of
desired amplitude into PA's input

2. At the PA's output, it will measure the magnitude of output signal (or
difference in input/output magnitude) in say dB ref 1V unit. This will
define Gain(magnitude) point at that particular frequency

3. At the PA's output, it will also measure the phase of output signal
relative to input signal (or in other terms, phase difference b/w input and
output signals) at that particular frequency. This will define Phase(deg)
point at that particular frequency

4. Now steps 1 to 3 will be repeated for all frequencies defined in
selected Bandwith and resultant graphs will be plotted resulting in Phase
vs Frequency and Gain (magnitude) vs Frequency curves.

5. This whole procedure will be done automatically by E5061B.

Am i correct in my understanding?Please comment.

Thanks & Best Regards
Nauman

• This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,