Tuesday, 8 July 2014

HiDes HV-202E DVB-T self-contained transmitter: Quality all digital live DATV from DSLR camera at last!

HiDes HV-202E DVB-T self-contained transmitter: Quality all digital live DATV from DSLR camera at last!

The HiDes HV-102E DVB-T self-contained transmitter has arrived at US$660 delivered. I ordered the USB version of this professional HDMI/HD-SDI 4 band (100 MHz - 2.5GHz) DVB-T TX originally, but upgraded to the stand-alone box instead. (see why latter). It works perfectly out of the box and is easily configurable for any modulation or media parameters.

I had a good experience with the HiDes DVB-T HD CCTV camera transmitter; see earlier post. As such I thought I would try their HDMI input DVB-T TX. Surprising similar, as will be explained.

The impressive specifications per HiDes:

There isn't much this box can't do! Any frequency (up to 2.5 GHz!), any band-width, any media modulation parameter. There isn't anything that comes close, at any cost.

I set it up on a channel my little 16" TV could receive (by cable with an attenuator) and connected up a Cannon 70D SDLR camera via HDMI and turned it all on. Tuned the TV and there was the picture of my very-messy study in all its digital video glory. See picture of box in action. I will discuss the hardware latter.

However it was not in Full HD, just SD. I had to fix that. The HV-202E connects to a PC via USB for configuration. Perhaps, not surprisingly it was the same procedure as the DVB-T HD CCTV camera. It seems so old-fashioned, but the interface is via a virtual com port. The modulation and media boxes are shown.

Australian amateurs can use a 7 MHz band-width with the same modulation parameters as our free-to-air TV, so that is what I wanted; and got. Similarly, with all that bandwidth, I wanted Full-HD 1080i at 30 fps. With a bit of fiddling, I had it: the TV and camera, although in poor light at night.

The white rectangle is an artefact of the 70D camera's auto-focussing. I discussed the problems of getting live clean video from a DSLR in an earlier post. Eventually Magic Lantern will release firmware to fix the problem; the 70D is not long released and a very popular DSLR for video as it has a very effective new auto-focus system.

TX box hardware

Not being backward at opening up new equipment to see how it works, see earlier posts, and noting there was a new version of firmware, the lid was off pretty quick.

The internals were initially a surprise, there was the HiDes USB version of the TX (the brown rectangular board complete with USB connector), as a daughter board to a box made for another purpose. The main box seems to be designed to input HDMI or HD-SDI sources, plus audio and output it as HD-SDI; consistent with a device for HD CCTV. The HiDes board takes what was the SDI output and converts it to DVB-T instead, just as it does with the HiDes HD-CCTV box camera via a daughter board. Very neat. Why design everything from scratch when a modification can be made to existing sophisticated hardware?

There is not much documentation on the HiDes board's chips. The key ones are made by ITE Tech, another Taiwanese company specialising in HD-CCTV and digital multimedia chips: http://www.ite.com.tw/EN/company.aspx. The main chip that can be seen is a IT9518, a member of the IT9500 series of transmitters for CCHDTV cameras via DVB-T, not surprisingly. The other chip has a cover or heat-sink obscuring its details.

The main box has a awesome array of very powerful, highly integrated, digital media chips (Google each for details):
  • ITE IT9507 transmitter for CCHDTV camera, presumably SDI,
  • ITE IT6604 HDMI receiver for HDMI input
  • GENNUM/SEMTEC GV7601 Serial Digital Video Receiver for SDI input
  • TI DM368ZCE ARM SOC Digital Media Processor
  • TI AC31061 Stereo CODEC for audio input 
  • Micron D9MTJ 2Gb DDR2 SDRAM
I was staggered by the capabilities of these devices; it used to take racks of equipment to do what this little box does. Intel CPUs have only incrementally improved over the last 5 years or so, whereas devices based around the ARM CPU imbedded SOC leap forward, as do the dedicated function chips.

The British ARM company http://www.arm.com/index.php is a story in itself that I won't go into here; eventually it fill be a case study in my other (neglected) blogs (see via profile)

Incidentally, there is a SD card socket under the daughter board for firmware updates.

Why not USB?

As noted at the start, I originally ordered the USB version of this HiDes TX, about $270, but changed my mind and spent the extra on the stand-alone box I describe here. The reason? Live capture of HDMI on a PC is a major hassle and is more expensive. HDMI is very complex, as is most things to do with digital video (and audio) in any form, including HDMI, HD-SDI and DVB. The capture cards or USB boxes are not cheap, around $250, and are not easy to use. Further, a fairly powerful PC is needed as much of the processing is done in software. To compound the problem, Windows 8.1 makes life difficult for small volume devices due to its improved and more secure device driver requirements, a necessity given the problems with cyber security. The live HDMI feed from DSLRs further complicates matters, as noted in earlier blogs.

I started with a HiDes UT-100C USB dongle, see earlier post. It works fine with a webcam, but I spent ages and money trying to get it to work with HDMI capture cards.

The stand-alone HiDes HV-202E TX works with no dramas. It is physically simpler to have a little box that does everything, than a collection of PC-based gear to do the same thing.

Where to next?

To a point, the HiDes HV-202E allows me to achieve my original goal of high quality digital video and audio, via a DSLR camera, to a DVB-T TX on 70cm. For that, I am very happy.

Next? I have spent more time writing this post than using the HV-202E; I still have much to learn.

My plan is to use the Black Magic Design ATEM TV Studio as the HDMI input, to allow the use of multiple cameras and media sources, as discussed in an earlier post. This will give me a very usable TV studio and DVB-T modulator in a very small package, maybe portable.

1 mW isn't going to get me very far. I have a 10W DVB-T amplifier from Darko in Austria. Using my improvised instrumentation, particularly the BladeRF as a spectrum analyser, I hope to get a clean, usable signal. I have the bits to make up an antenna and a mast to mount it, although still needing work to get the rotator operational.

Then there is the HiDes DVB-T repeater that has been gather dust... And a 4W 23cm amplifier, also from Darko. Then to get a RTL DVB-T dongle to work as a 23cm receiver.

No comments:

Post a Comment