A REF TEK 72A 3-channel portable seismic recorder consists of 3 units:

1. The data acquisition system (DAS) equipped with 24-bits digitizer and 2.5 MB static RAM. Up to eight active data streams may be specified. A data stream encompasses the included channels and preamplifier gain, sample rate, and one of seven recording modes, for example-continuous, event-triggered, or time-windowed recording.

2. The Hard Disk Recording Subsystem where the DAS copies the data from its RAM. The disk capacity is 4 GB allowing one to three months of data storage depending on sample rate.

3. A GPS receiver/clock system. At the time the recording parameters are downloaded, the analog-to-digital converter (ADC) is synchronized to Universal Coordinated Time using the REF TEK Receiver/Clock as a time source.