Four defense/aerospace communications suppliersPentek, DRS Signal Solutions, Digital Receiver Technology, and Eclipse Electronic Systemsannounced their intentions to develop products using a new standard recently approved by VMEbus International Trade Association (VITA) called VITA Radio Transport (VRT). The standard facilitates easier system integration for software-radio applications by providing compatibility between RF receivers and signal processing equipment via transport-layer protocol.

VITA's VRT working group expects to initiate recognition of VRT as a national standard within the next six months.

The VRT standard defines a transport-layer protocol that promotes interoperability in a wide range of applications, including spectral monitoring, communications, and radar systems. VRT enables high-precision time stamping to provide time synchronization between multiple receiver channels. The standard building block to support data streaming for software-defined radio (SDR) applications.

With the emergence of high-speed serial data links it is now possible to allow wide-bandwidth communication signals to be exchanged using a packetized format. VRT standardizes this packet structure with features specifically useful to defense and aerospace communication applications.

John Rynearson, technical director at VITA stresses how important standards like VRT are to the SDR Forum and its members. Rynearson explains that when combined with application programming interfaces such as the SDR Forum's approved Smart Antenna API or its emerging Transceiver API, these standards promote an ecosystem of vendors with interoperable radio technologies.

The VRT protocol was created by and is supported by a wide industry base of organizations, including RF receiver manufacturers, digital signal processor manufacturers, data recorder manufacturers, prime contractors, and government agencies. Paul Mesibov, director of Engineering at sponsor-company Pentek, asserts that "VRT breaks new ground in providing a systematic way for vendors to specify and document the way complex communication equipment can function so that system integrators can more easily configure these systems."

DRS Signal Solutions is providing VRT as an option for all new receiver and recorder products. It currently has several VHF/UHF and recorder products available with VRT, and will soon offer HF and SHF products.

Digital Receiver Technology, an SDR company and sponsor of the specification, has also begun transitioning its interfaces to the VRT standard. "One really great feature of this standard," says coauthor Dick Shaner of DRT, "is that it provides a standard way to combine a digitized RF/IF signal and its associated metadata into one unified information stream. This ensures that the digitized signal can always be interpreted properly, eliminating a great deal of potential confusion at the system level."