I want to measure audio frequency and ultrasonic in air and in water(under water), and then analyse the data. So the instrument must fit the following:
1. Frequency range: DC to 5 MHz or 10 MHz;
2. Frequency analyser(FFT Function);
3. Proper probes or sensors by which I can measure audio and ultrasonic frequency in water and under water.
How to choose your products, please give me some advice.
Thanks a lot!