Posted on: 23 August 2018   By matthew.coolidge

Transducer Module Internal ElectronicsNew Circuit Board

FarSounder sonars use a sophisticated data acquisition system to digitize underwater acoustic signals. These custom electronics are designed in-house and are one of the reasons 3D forward looking sonar is possible today. Recently, the electronics in our Transducer Module underwent a major refresh bringing some of the latest technology to our products; one of the ways FarSounder is always looking ahead.

FarSounder-500 Transducer ModuleFarSounder-1000 Transducer Module

Inside the Transducer Module is a circuit board custom-designed to collect analog signal data on 48 channels simultaneously, filter the data appropriately, digitize, and communicate over Ethernet. This circuit board was originally designed in 2008, and with it came the launch of our two flagship products, the FarSounder-500 and the FarSounder-1000. Both units feature this data acquisition circuit that is highly specialized for producing our 3D forward-looking sonar images.

As with all electronics, new components with more capabilities and features are always coming to market, while older ones are becoming unsuitable for new designs or even discontinued entirely. As we faced supply challenges with some of the components we use, it was clear that it was time to revisit our circuit design.

After reviewing many options for data acquisition topologies, we opted to stay with the same physical size and shape circuit board, as well as the same digital communications structure we had already established with the previous design. This would allow us to retrofit older products and maintain the same mechanical package. We would, however, take advantage of new cutting-edge analog-front-end devices, as well as a new FPGA to control the devices and add additional layers of signal processing in the hardware. All of these new devices necessitated a new power delivery system, circuit routing, and firmware authoring.

Originally developed for medical imaging systems, the new analog-front-end devices replace the hundreds of components that made up our preamplifier and analog-to-digital-conversion circuits with the addition of advanced onboard signal processing. The result is significantly improved signal acquisition performance, filtering, and out of band noise rejection.

The new design adds capabilities to monitor and respond to temperature changes over all areas of the board, keep track of energy usage, and circuit fault monitoring and diagnostics.

With so many new devices on the board, the FPGA firmware was completely overhauled to support new internal features while guaranteeing timing across the board to all of the devices.

This new circuit board was designed, routed, fabricated, and assembled with the first prototypes arriving in July of 2016. These were used for initial testing and firmware development. Only minor changes were selected for the production revision that started with deliveries in late 2017. With the new architecture, even more capabilities and greater performance of the system can be realized in future revisions of the firmware that can be delivered remotely to our customers.

The new design has even more bandwidth capability and a more modular and compact circuit design that may allow for future reductions in physical size and integration opportunities. These advances are some of the many things FarSounder is doing to continually improve on our products and provide our customers with the best forward looking sonar solutions.

If you have a FarSounder system that you would like upgraded, we would love to hear from you! Contact us for more details!