Is this Raspberry-Pi-based device the world's smallest DVB (Digital Video Broadcasting) transmitter?
I was first alerted to the benefits of open-source some years ago while talking to a couple of very experienced engineers. These guys, who worked for a multi-billion-dollar company with a global footprint, had been asked by their manager to complete a project in a ridiculously short time frame.
They concluded that their only hope was to use open-source, which was an unusual decision for a company of that size and a bit of a culture shock. Open-source software has a long pedigree, of course, but most companies do not open up their hardware designs.
Lime Microsystems is one company that evangelizes an open-source philosophy and provides full details of its wireless chips. As a result, the open-source community has embraced the software defined radio (SDR) boards from Lime and is creating some exciting applications, which greatly extend the functionality of the device through the use of a natively enabled app store.
This digital TV transmitter, which is based on a combination of a LimeSDR Mini and a Raspberry Pi Zero, provides a perfect example.
This setup processes the camera output into a DVB2 compliant transport stream and onwards to the SDR, while the receiver features a decoder and display chain to drive an HDMI output (it also includes a spectrum analyzer). The demo uses RF tuned to 1.2GHz, which sits within the 10MHz to 3.5GHz range of the Mini. Designers can download the app to provide a DVB (Digital Video Broadcasting) video link and customize it to their exact requirements.
The open-source community is busy creating a wide variety of wireless applications using LimeSDR products, and then making these applications available for "app enabled" products. In addition to the video example discussed above, there are already designs for narrow and wideband FM transceivers, a spectrum analyzer using a UDOO X86 single board computer, a GSM base station using a Raspberry Pi and -- with the addition of a Lime frequency range extender -- the LimeSDR transmits and receives LTE signals at 10GHz.
With thousands of Lime SDR boards in the hands of enthusiastic engineers, the number and diversity of open-source applications is set to snowball.
I'm not in a position to comment on the speculation that this is the world's smallest DVB transmitter as some are saying, but it could easily be the fastest (and cheapest) one to design.