I have a suggestion, if you would like to do a bit of math.
1. Start with the equivalent circuit of a transformer... http://www.infolytica.com/en/markets/appspec/cstudies/Transformer%20e-circuit_2Dcs.pdf
2. With say a load connected across the secondary, convert the circuit on the secondary side to the primary side. These relations are pretty standard, which you will find in any book on transformers.
3. I will start to throw in some terms now and hope to not throw you off. Write down the "laplacian equations" for the circuit. These equations have 's' terms instead of 't' (time).
4. Find 'transfer function' between input and output voltages. All you need now to graph the 'bode plot' of the transfer function.
All said... if your load is not resistive, you can expect a second order response at your output. Sorry... if my response didnt ring any christmas bells.
Do you need to know the math only, or do you have a transformer of which you are trying to verify the actual frequency response? If you only need the theory, than answer # 1 will mostly suffice, if you need a practical way, than you will need to supply more information such as : is this a power transformer, audio, or RF? Frequency range required, etc. The more the better. There are several simple ways of doing this, if you don't (and from your question I guess you don't) have a spectrum analyzer,
Always bear in mind that questions of that type must be made more clearly, to encourage this knowledgeable group to help you.
Frequency Response
Re: Frequency Response
