The revolutionary PHABRIX SxA.

Bob Pank#

Author: Bob Pank#

Published 1st March 2011


The revolution in screen technology has seen a massive miniaturisation of most test equipment in the last ten years, and this coupled with a large increase in the amount that can be fitted into a small package courtesy of VLSI has meant that a new breed of hand held test and measurement devices have come onto the market.
The PHABRIX Sx range is just such a family of devices. The PHABRIX Sx family will generate test signals in all the digital domains (SDI, HDSDI, 3GSDI, AES) and will also measure and analyse the same range. The SxA has additional features to support AES audio, the SxD specialises in dual link HD (usually 2 x 1.5 Gbps streams) and the SxE adds eye and jitter measurements to the specification of the SxA.
I was supplied with an SxA to test over a week on an HD build, putting an HD shoot into a studio with already existing SDI, with some SDI remaining in place for monitoring. The PHABRIX is supplied with a padded bag with separate compartments for the unit itself, the mains charging unit and a CD with manuals and some extra patterns to load if desired. The unit itself is made to the highest standard, with top quality connectors at either end, which are slightly recessed. This helps to protect them and both ends of the unit have rubber overlays which should help in the event of the unit being dropped. Within the two protectors the case is rugged aluminium with a high resolution screen central to the main face and a row of buttons (soft keys) under the screen. The power on/off is to the top right hand side of the main face, with navigation and selection buttons for menus underneath.
At one end of the unit are the five main signal processing inputs and outputs. The SDI output will generate SDI and HDSDI (720, 1035, 1080 at or below 1.5 Gbps in all frame rates, with interlace or PsF) and 3G HDSDI (3 Gbps, p50/60) all with embedded audio. The AES output will generate a single AES pair in unbalanced format. The inputs will monitor signals in the same formats, but the input and output do not have work in the same format, being totally independent of each other, and this is one of the great strengths of the SxA, especially when configuring up/down converters, as the signal can be generated in one format then checked coming back in the converted format, all on the same hand held instrument. The final BNC connector is an input for genlock, which can be bi-level, tri level or SDI. This genlock can also be used to check for the presence of an analogue signal, but it can't be viewed or analysed. The opposite end of the SxA has the charging connector, USB and LAN connections, plus an audio monitoring output on a 3.5 mm jack.
The LAN connection allows control of the SxA remotely, and Javascript allows the unit to be controlled from a web browser independent of the operating system hosting that browser, so the connection will work with Windows, Linux or Mac OS X with the minimum of configuration.
Bearing in mind the unit is actually computer based, it boots up very fast from cold. The initial start up screen has a small Linux symbol (Tux the Penguin) but then disappears to offer the home screen, or main menu page. This screen summarises the complete state of the unit, with descriptions of the formats of the incoming and outgoing signals, symbolically linked by lines to the BNC sockets which those signals are on. The buttons at the bottom of the unit are soft keys, with the legend for those keys on the screen just above each button. One key rule makes the user interface simple, powerful and easy to use without having read a manual. That rule is the extreme left hand soft key always (with one or two obvious exceptions) takes you back to the home page or main menu, from which you can easily select one of the key options. There is one main layer below the home page with virtually all the options for that area of the generation/analysis process on one screen, all of which can be accessed via the up/down/left/right/OK keys to the extreme right of the unit. It's this powerful yet simple user interface that allows the engineer working against time pressures to become familiar with the unit in minutes and then to be able use it easily and intuitively in the field without any additional thinking taking away from the solving of the main problem. Over the week I used it, I got into an easy pattern. Get the unit out, turn it on, select generator or analyser, use it.

Let's quickly look at the video test signal generator. I obtained these images of the whole unit via the web browser control of the SxA via LAN mentioned in last week’s edition of Tv-Bay.
It's possible to select a standard for the output, a test pattern, and to put an ident on the pattern used to confirm any signal viewed is from your unit. There are a large selection of patterns and extras can be loaded from USB or other sources. Regardless of which screen you are in the top line of the display always gives you global information about the input (video and AES), the output, the state of the genlock feed and the log if running. As well as the usual signals you would expect, a zone plate to test for compression artefacts and aliasing is present. Once the unit has been supplied with a reference feed it can take the place of a much more expensive rack mounted Test Signal Generator and I've just used it as such in the aforementioned HD install I did. The video side of the generator is impressive, but the audio side of it is awesome.
You can generate test tone on all four groups of audio that can be embedded in SDI, and therefore have control over 16 channels of embedded audio. The audio can be turned on or off group by group, and the parameters of each channel individually set. You've got the option of fixed or variable tone, with the frequency specified in a drop down box, and a master level. You can also select any pair in any group to be the AES output or the real stroke of genius, you can select an audio pair on the embedded video input, which means that the unit will de-embed audio for you. The same trick can be done on the input side, where you can embed audio of your own choosing onto the test signal, as a back door way of getting AES audio routed across a video matrix.
It's time to turn our attention to the analyser side of the SxA. The analyser has four options you will need and use in a hurry, the incoming picture, audio meters, wave form monitor and a vector scope. The picture can show either input or output, and will go full screen if the main menu key is pressed twice in succession. Audio meters will show inputs and outputs in a very highly configurable fashion, and you can see inputs and outputs on the same screen. The wave form monitor and vector scope produce very familiar displays, with the options you would expect on a mainstream, rack mount version of the same unit. There is a 5th menu, Signal Data, which allows you to seen the actual values of the individual video samples, but that's an optional extra.
The System menu makes you realise just how much is crammed into the SxA. In this section, you'll find a memories option, which will allow you to save any set up you've done on the unit into a file to be recalled. You can choose exactly which areas of the unit get saved, and can very quickly get back to any of your favourite set ups or testing situations. You can also save those memories to a PC for back up purposes, or to copy to other units.
The logging menu is another powerful tool. No need to watch things for ages waiting for video faults! Simply connect the unit and turn logging on. It's worth having the correct time set on the unit, as it time stamps events, and there is the facility to put time markers manually into the log, so you can easily remind yourself when logging started and ended. The log can be configured to beep when there is any event or logging.
The last option in the main menu is the Speaker one. It's self explanatory. That's the best thing overall about the Phabrix SxA, that everything is obvious and easy to use if you have technical background in TV. The menu system and the design of the user interface means that the manual will only be needed for the most intricate of set ups, otherwise the user interface guides you through to what you need very intuitively. Underneath that menu system is a very powerful instrument, and one that for me in the 10 days I had it proved its worth time and time again. On a build with lots of kit from different people, it saves so much time in the "we're not getting it\" and "all right leaving me\" game of ping pong.

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