Laser Interferometer

Signal Processing - Digital & Efficient

The signal processing unit is a major and important part of a laser Doppler vibrometer (LDV). The signal processing unit observes and records the light intensities in the photodetector of the Mach-Zehnder-Interferometer, which is the core of every LDV. The recorded data are converted in real time into the displacement, velocity, and acceleration information of the vibrating device under test. 

Optomet continuously aims at providing the most innovative and efficient solution for modern laser vibrometry. Therefore, Optomet equipped each vibrometer model with an internal FPGA from the very beginning of the company's history. Nowadays, Optomet has almost 20 years of experience with digital decoding and provides the most innovative and technically matured digital signal processing units available on the market.

Digital Signal Processing

Optomet relies on an end-to-end digital signal processing with FPGAs allowing a fully digital read-out of the measurement data. This avoids the drawbacks of analog demodulation,  which may result from component aging, temperature dependencies, noise, and non-linearities. Vice versa the benefits of Optomet’s end-to-end digital signal processing are:

  • Significantly higher signal sensitivity

  • Better data resolution

  • Higher signal processing stability

The result is an extremely low noise level even from poorly reflecting measurement objects, which guarantees precise measurement data in nearly all situations.

Digital & modular decoders - ultra-fast-DSP

The Optomet ultra-fast-DSP combines efficient algorithms with specialised, high performance processors.

  • Decoders are integrated into the vibrometer, no separate hardware is required. They can be upgraded via Ethernet at any time  in a matter of minutes.

  • Due to their energy-efficient design Optomet vibrometers can be passively cooled and be operated independent from grid power.

  • Signal processing is done in real time. Special linear FIR filters allow for reliable and precise data even under the most challenging conditions.

Measurement data - Read-out

Optomet Laser Doppler Vibrometers can decode the displacement, velocity, and acceleration information of the vibration measurement data simultaneously and in real time. 

  • Each second 160 million values of these data (160 MS/s) are recorded and passed to the outputs.

  • Data are transferred through a standard GBit-Ethernet port and simultaneously via three BNC connectors for the integration in analog test environments.

  • A data resolution of up to 32 Bit, corresponding to a dynamic range of 220 dB, can be selected. Multiple vibrations with orders of magnitude different amplitudes and frequencies can be measured simultaneously. 

OptoMET Laser Doppler Vibrometer - High Dynamic Range

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