+44 (0) 1954 231 494
Cambridge Ultrasonics
Cambridge, UK
Consultancy service in physics, electronics, maths & ultrasonics

Cambridge Ultrasonics

Menu of services

Electronic Design - at a glance

  • Digital design - DSP, FPGA, CPLD
  • Firmware - VHDL and C++
  • Analogue design - to 100 MHz
  • Microwave - lumped component and strip-line
  • PCB design - multilayer and matched impedance
  • International standards - EN61010, CE mark
  • International standards - intrinsic safety
  • Interfacing to computers - PCs & Windows

Electronic Design

Electronic engineers at Cambridge Ultrasonics have many years of experience in designing electronic circuits for instrumentation including low-power and modest power applications up to about 4 kW. We design to meet international standards, commonly EN 61010 "Safety requirements for electrical equipment for measurement, control and laboratory use". We also have experience in designing to meet standards for CE marking and intrinsic safety for explosive environments.

Our workshops are equipped with first-class equipment, such as DSOs sampling at 4 GS/s with analogue bandwidths of 1 GHz. We also have logic analyzers, digital waveform synthesizers, vector impedance measurement equipment, RF power amplifiers and our own visualization equipment for debugging ultrasonic systems.

We have worked on many DSP designs, using C++ for programming. For CPLDs and FPGAs we like to program in VHDL.

If a computer is involved the preference is to use PCs and to write Windows control and analysis programs. For low-cost the preferred route is to select commercial plug-in cards and to write custom software in C++ for specific data acquisition applications. In stand-alone applications, without the need for an operating system, we recommend using a DSP, particularly for real-time applications. We use UML methods to perform top-down design of software.

An example of recent electronic design was a medical instrument that used a lock-in amplifier to make a measurement. The client wanted to test at several frequencies simultaneously and was considering using white noise excitation and FFT spectral analysis. However, there was a disadvantage in this approach that Cambridge Ultrasonics identified in a technical audit. The client then asked Cambridge Ultrasonics to develop a digital system with 10 lock-in amplifiers on one printed circuit board. The circuit also had a DSP to control all functions and perform some high level processing and several FPGAs and CPLDs to provide other functionality. The pcb had 11 layers with impedance control on the data  bus running at 80 MHz. Note that there was no ultrasonic component in the design.

Another example of recent electronic design involving no ultrasonic component was the re-engineering of a microwave amplifier. The client presented a microwave amplifier that was not designed to meet modern standards of safety and was not reliable. Cambridge Ultrasonics was asked to re-engineer the device as an OEM assembly. After agreeing a specification with the client we started the design work and completed the first prototype about 6 months later. The client then wanted some modifications and about 4 months later a second prototype was delivered to the client. A further three prototypes were made.