Bespoke Systems

Interleader has the capability to develop bespoke systems for customers, either as a design only, or as a design and build activity working with a number of local UK quality suppliers for PCBs, assembly, fabrications and general assembly. The following are examples of a bespoke development.

Cellular Radio Module

To support worldwide cellular radio connectivity and integrate into a range of existing and planned products a new design of cellular radio was required that would operate on 3G, 4G and LTE networks.

The cellular radio chosen was the Telit HE910 family of devices. The HE910-D is used for UK/EU/RoW and the LE910 NA V2 for the North American market. Other variants from the range can also be accommodated.

The module features an on-board switch-mode power supply with an input range of 5-24V DC. The device's USB port is brought out for programming and diagnostics and there is an on/off button on the PCB. A latching micro SIM carrier is provided and a number of the GPIO connections brought out to a header.

Communication with the module is via the built in RS-232 transceivers at up to 115.2kb via a 9way D layout header. There is provision to fit a diversity antenna and, where a suitable module is fitted, a GPS antenna can also be connected.

VHF Signal Generator

A self-contained, software controlled VHF signal generator was required to provide RF output at up to 150MHz and with an output amplitude from +3dB to -40dB into 50ohm.

The circuit shown to the right includes an Analogue Devices AD9952 high precision Direct Digital Synthesizer, Microchip PIC18F45K20 CPU, high precision crystal oscillator, output amplifier and filters and 4 power supplies.

One of the RJ45 connectors is used to interface directly to a shaft encoder for rotary input for both frequency and amplitude and the other connects to an LCD and keypad interface (see Interface Products section) to provide all of the required keypad controls and digital readout of frequency and amplitude etc.

The board is 60mm long by 50mm wide and 18mm high (over the connectors) and provides a very compact solution.