Full Wave Form Time-domain IP Data Acquisition

We present and discuss some examples of full wave form resistivity-IP data recorded at one site in Sweden and one in Malaysia. The examples show that highly detailed recordings can be made, and that various types of noise can be clearly distinguished. With such detailed information about the character of the signal and noise it is relatively easy to develop algorithms that can remove the noise without biasing the extracted data. Tests using a pure square wave as measuring signal show that information relating to the chargeability of the ground are as clearly visible as in traditional time-domain IP-data, and it should thus lend itself well to extraction of the spectral IP information. An advantage of using square wave for time-domain SIP over frequency domain SIP is that data acquisition can be much faster, furthermore it would be more time efficient than a traditional time-domain IP signal. The results also show that the transmitted current wave form is almost ideal, whereas recorded output voltage varies to a significant extent. This may be due to, for example electro-chemical processes, and a constant voltage transmitter would not have produced current wave forms with such regular shape.