Chapter 2. Introduction

Thank-you for purchasing a Güralp Affinity.

The Affinity, a digitiser with combined storage and communications module, is a flexible and expandable tool for connecting analogue and digital instruments to your network.

Inside the robust, waterproof, stainless steel casing is a 31-bit, high-fidelity digitiser with state-of-the-art timing precision and enhanced acquisition module capability. Designed for data quality and durability, the Güralp Affinity is a stable and robust Linux-powered unit with on-board storage and networking facilities.

Built for challenging environments, the Güralp Affinity is suitable for post-hole and bore-hole deployment or can be wall-mounted for vault applications. The Güralp Affinity can be fully controlled and accessed via a web interface suitable for both expert and non-expert field staff.

2.1 Applications

• Borehole

• Vault

• Networked Arrays

• Earthquake early-warning systems

2.2 Key features

• Four low-noise 31-bit analogue-to-digital conversion (ADC) channels (three primary plus one auxiliary)

• An eight-channel version is also available

• Ultra-low-noise: 138 dB of dynamic range at 100 samples per second

• 16 environmental multiplexed ADC channels

• Sensor control lines (LOCK, UNLOCK, CENTRE) automatically detect whether connected instruments use "active-low" or "active-high" logic.

• Triggering/events subsystem capabilities including STA/LTA, level (threshold), software triggers, per-channel voting and peer-to-peer network voting

• Four concurrent output sample rates (continuous or triggered) up to 4,000 samples per second

• UTC time-stamped data using a low-power GPS receiver

• Multi-user Linux operating system with full network support

• On-board Web server (HTTP and HTTPS) allows full remote configuration of digitizer parameters and broadband sensors, including remote lock, unlock and centre

• 16 to 64 GB of on-board storage. Additional connection for external USB storage

• Built in calibration signal generator: step, sine or broadband

• Supports multiple data formats, including GCF, GDI, miniSEED and CD1.1

• Specifications independently verified by Sandia Laboratories