Patent for Unformatted Serial Data Transmission Issued to CDL Engineers
A recent patent issued to Matt Morgan and Rick Fisher of the CDL makes it possible to transmit digital data over optical fiber, or any data link, with far less overhead in the front-end than conventional digital data links would allow.
Conventional digital links rely on rather elaborate data formatting and packetization at the transmit end to enable decoding at the receive end. By using the statistical properties of the noise omnipresent in all radio telescope observations, management of the data link can be deferred entirely to the receive end (off the telescope) with no prior formatting of the data at the transmitter, reducing the size, power dissipation, and RFI generated by the digital electronics inside the telescope. These improvements facilitate the construction of large-format integrated focal plane arrays with the stability afforded by early digitization and digital data transmission. That stability enhances the longevity of calibrations for digitally-corrected receivers, such as Phased Array Feeds (PAFs), and may prove crucial for the very high-dynamic range imaging that is key to future planned radio astronomy facilities.
Although the initial theoretical basis for the technique assumed a background spectrum of Gaussian-distributed white noise, laboratory experiments have shown that the data link is very robust in the presence of real-world signals, such as RFI, over a wide range of operating conditions. The same hardware could be applied to a broad range of sampled data streams, such as scientific and medical instrumentation, and especially imaging applications where the data rates are very large. Whether active or passive, these systems all rely on the extraction of a signal of interest from a noisy background with maximum speed and fidelity, and with minimum overhead at the sensor node. For similar reasons, this technique would also apply to radar and sonar systems, both commercial and military, and to security screening platforms. It could also be used in industrial environments for process monitoring and product inspection. In each of these cases, the development described in this patent effectively provides system designers with an "ADC on a fiber" to incorporate in their applications for improved performance.
