The Güralp CMG-DM24 multi-channel digitizer is a state-of-the-art digital module for seismic data. It can be supplied in several different formats:
A stand-alone DM24 (below) can be installed with existing or new analogue sensors. Conversely, a modular digitizer is fixed to, and becomes a physical part of, a Güralp seismometer. These can be supplied with new instruments, or retrofitted to CMG-1T, 3T, 3ESP or 40T seismometers at the factory. A modular digitizer benefits from the sensor's isolated, clean and stable environment and allows it to operate at optimum noise levels and precision
The DM24 can also be supplied in borehole sonde form, with optional strain relief accessories. All these units operate identically, although the connector for the borehole unit is necessarily more compact.
A DM24 is especially powerful when operated in conjunction with a Güralp data module such as the CMG-DCM or AM. All three types - sensor, digitizer, and data module - can be customized to meet your installation requirements.
A built-in Digital Signal Processor (DSP), which can provide simultaneous multiple sample rate data streams at user selectable rates. Up to 6 streams of data for each component are available at sample rates from 1 to 1000 samples/s.
A precision microprocessor-controlled time-base synchronizes the Analogue-to-Digital Converters and the DSP, as well as providing time-stamps for data blocks.
Time synchronization to an attached GPS receiver or from a remote time source.
An ARM microprocessor, which formats and buffers data in an on-board 256k RAM ring buffer.
Efficient data storage and transmission using the Güralp Compressed Format (GCF).
RS232 serial data output at user-selectable baud rates, with automatic modem dial-out facility.
Built-in microprocessor system configuration and sensor control, including locking and unlocking, centring and calibration.
Low system power consumption.
Flash EEPROM for program code and filter coefficients.
High-impedance, low-noise, differential input pre-amplifier modules with adjustable gain.
Internal electronic thermometer provides temperature measurements at an accuracy up to ± 0.33 °C, with a linearity of ± 0.5 °C.
Optional Flash memory storage.
Optional IEEE 1394 FireWire interface, allowing you to download GCF data directly onto a compatible disk by simply plugging the disk into the FireWire connector inside the casing, and monitoring progress on the built-in LCD screen.
Optional USB interface, enabling fast data transfer direct to a PC or other recording device.
The DM24 can be connected to two Güralp analogue sensors, or up to six conventional single-axis seismometers, through its SENSOR A and SENSOR B connectors. (Single-sensor and integrated DM24 units have only SENSOR A connectors). Signals from these sensors are digitized to 32-bit precision, initially at 2000 Hz. Data is output through the DATA OUT serial port of the digitizer in the flexible GCF format, either to a PC or a Güralp data module. Timing signals are gathered from a GPS unit connected to the single GPS port.