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Consumer Product Review By LEO SIMPSON Philips’ revolutionary wide-screen TV receiver Recently, Philips released their newest wide format TV receiver onto the Australian market. Called the Matchline 76cm, it has every conceivable feature that could be crammed into a TV receiv­er, including Dolby Surround Sound, Picture-inPicture, Teletext and 100Hz digital flicker reduction. We borrowed a sample unit & watched it long & hard to bring you this report. 4  Silicon Chip T HIS IS NOT THE FIRST WIDE-SCREEN TV receiver from Philips, as they released their first model in Australia about two years ago. However, this 76cm Matchline is a completely new model with many more features and a lower price. So why would you want a TV set in the new 16:9 format? Given that there is not much program material at present, Philips has worked hard to make the new set as enticing as possible. If you have a laser disc player with movies recorded in the wide screen 16:9 format you will immediately appreciate the benefits of the new Philips receiver. The wide screen has a more dramatic presentation so that when you come to view a convention­al TV set with its 4:3 screen it seems to lose a great deal of visual impact. Before we go much further, we should explain these formats of 4:3 and 16:9 for the benefit of readers not familiar with these terms. Conventional TV sets have a screen which is four units wide and three units high. For a 63cm set (diagonal measurement), the screen will be nominally 50cm wide and 38cm high. Movies on the other hand, and the new HDTV standard, call for a 16:9 screen format and so the screen is 1.77 times as wide as it is high – much wider than a normal TV. When movies are broadcast by TV stations they have several options. They can aim a conventional camera at the movie screen and thereby clip off the edges of the screen; they can pan the camera to take in the action on the screen or they can broadcast in “letter box” format which results in a black strip at the top and bottom of the screen. This latter option is used quite often these days on SBS television and also by commercial TV networks when they are rolling the credits at the start of movies. Whichever way they do it though, the result is hardly what the movie producer intended. In producing this widescreen set, Philips give the viewer the option of watching normal programs in wide-screen format – the “superwide” mode. This means that you do not have to watch 4:3 programs with a black band down each side of the screen – you can expand the picture to fill the screen and in doing so, you lose very little at the top and bottom. Contrary to what you might expect, this does not lead to grossly distorted pictures with balloon faced people, extra long cars and so on. Philips has been much more clever than that. But before we explain what they have done, let’s talk about the general details of the new set. The new set is big and heavy but not overly so. It is 836mm wide, 591mm high, 593mm deep and weighs close to 55kg. The main component of the weight and the reason for the consider­able depth of the set is the tube. Glass is heavy and the tube needs to be quite deep to provide for such a wide deflection. All of the cabinet is plastic with a dark matt finish, very much in the style of today’s TV sets which are quite subdued in appearance. Also as with most of today’s sets, the new Philips Matchline is designed to be controlled exclusively by the in­frared remote handpiece; very few Philips’ new 76cm Matchline TV receiver has a 16:9 format picture tube & this gives a much more dramatic presentation than a conventional TV set. Particular features are the 100Hz flicker reduction circuitry & the scan velocity modulation system to enhance picture highlights. functions can be controlled from the set itself. Those that can are in an array of buttons down the lefthand side of the set and are as follows: Power On (standby), Video (select), Install, Volume (up/down) and Channel (select). These are grouped with RCA sockets for video and stereo audio inputs and an S-video socket. In practice, apart from the Install button which would only be used at the time of installation, these buttons would never be used unless the remote control handpiece was temporarily out of order due to flat batteries. In fact, the only control on the set which is likely to be used on a regular basis is the main power switch which is on the lefthand side of the cabinet. Philips recommend that it be used to turn the set off at night, thus avoiding any standby power drain, and also because when the set is turned back on again, the picture tube will auto- matically be degaussed, to maintain good picture quality. As you might expect, the remote control handpiece has a myriad of buttons and these can be quite confusing and hard to follow for those who are not technically inclined. With that in mind, some genius at Philips has come up with the idea of provid­ing a second remote control which provides just the basic func­ tions. This is doubly handy when the main remote control gets wedged in behind the lounge cushions and one is desperate to mute the sound, for example. Many features Even in a very long and detailed review it would not be possible to cover all the technical and user features of the Philips set. After all, it comes with two owner’s manuals, a brief one and the comprehensive one. Two infrared remote controls are supplied with the receiver, one with all the bells & whistles & the other with just the basic functions. Both have a very good operating range. August 1994  5 This photo shows one of the many on-screen menus which are brought into operation with the remote control. This one is for picture features & shows CTI highlighted. CTI stands for colour transient improvement & this feature mainly enhances the red details in the picture. The comprehensive one has 78 pages and it is only in English, not multiple languages! There­fore we’ll just discuss the main features in broad detail. Apart from the wide screen, the Philips Matchline has a brace of features which are all linked together technically: 100Hz flicker reduction, picture in picture, digital noise reduc­ tion, colour transient improvement (CTI), multiple system compa­tibility and still (freeze frame). A big problem with television viewing in Australia (and other countries which use 50Hz AC mains supply) is picture flick­ er. This becomes much more noticeable in large screen sets and even more noticeable in wide screen sets because the peripheral vision of the eye is so sensitive to flicker. Clearly, a wide screen set without some sort of flicker reduction would be un­pleasant to watch. This set and others on the market combat the problem by scanning the picture at 100Hz instead of 50Hz. That one change requires an enormous increase in set com­ plexity because it immediately means that a digital field store is required. Just a few years ago, digital field stores were only to be found in TV studios and they cost immense amounts of money. In essence, the luminance and chrom­inance signals are digi­tised by an analog-to-digital converter (ADC). Conversion takes place at a sampling frequency of 16MHz which, by the Nyquist criterion, limits the video bandwidth to 8MHz. This is wider than the 7MHz bandwidth required in Australia but this is a world set, capable of receiving TV broadcasts in any of 27 different for­mats, covering all the variations of PAL, NTSC and SECAM. After sampling, the digitised This series of on-screen photographs shows the images produced from a crosshatch pattern. Above left is the 6  Silicon Chip picture information is written to a bank of video memory. It is then read out twice, with a clock frequen­cy two times that used to store it. The detail of this system is a great deal more complex but suffice to say that scanning the fields at 100Hz instead of 50Hz is not the complete solution. While it solves broad area flicker (which is noticeable even on VGA screens scanned at 70Hz), it does not solve alternate line flicker. This is often very noticeable when TV stations put pictures in small boxes on the screen. Philips has solved the line flicker problem by not just doubling the vertical scan frequency to 100Hz but by also doubling the scan frequency as well, to 31.5kHz. Note that this is not exactly twice the PAL scan frequency of 15.625kHz but it is twice the NTSC scan frequency of 15.75kHz and ties in with the world nature of this set. Not only that, but the set uses a complex algorithm whereby alternate lines may be scanned in ‘ABAB’ mode for stable parts of the picture where flicker would be noticeable and in ‘AABB’ mode where the picture is moving and so flicker is not perceptible (where A and B stand for alternate lines in an interlaced picture). The result is a picture on the screen which is so stable and flicker-free that it is uncanny. If the picture is stationary as well, it is absolutely still, just as if it came from a slide projector – it is that good. Digital noise reduction Digital noise reduction (DNR) is a feature which is only made possible because of the fact that there is actually enough video RAM to store two complete fields. The set uses an algorithm pattern produced in 4:3 mode, together with a PIP display. Superwide mode (above) expands the image horizontally to compare the video signals, line by line, with the previous field and thereby distinguish between random noise (snow) and legitimate variations in the video signal. DNR can be introduced in two stages with the remote control and it can make a worth­while improvement in signals which have a modest noise content. However, it also results in a minor loss of detail on less noisy signals and so it is often difficult to decide whether to switch it in or out. Colour transient improvement (CTI) is another byproduct of the digital video processing and gives sharper transitions for colour picture information. The remote control gives you the option of turning CTI on or off but unless you know what to look for, it is hard to tell the difference with it on or off. Its main effect is to sharpen up red signals which can otherwise be quite blurry. Once you have noted the effect, you will leave the CTI switched on because it is beneficial. Picture in picture Picture in picture (PIP) might be regarded by some as a gimmick but in practice it is a very useful feature which allows you watch one channel while keeping an eye for the start of a program on another channel. Not only does it require a digital field store so that the two pictures can be synchronised together but it also needs two complete video processing chains: two TV tuners (UHF & VHF), two IF strips and so on. Hence, you can watch any video channel on the main picture and any channel on the PIP. You can even display a Teletext picture on the full screen while continu­ing to watch (and listen to) the PIP. Finally, as a byproduct of the field The chassis of the new Philips set is essentially a large motherboard with quite a few smaller boards plugged into it. Not shown is the superwoofer enclosure which is attached to the rear cover. store, it is possible to independently freeze the main picture using the STILL button on the remote and the PIP using the FREEZE button. This is not a particularly useful feature but it can be amusing to freeze some TV personalities while they are talking. Other picture enhancements The new Philips set has two other picture enhancements, one of which is extremely worthwhile and one which is arguable. The first is the SCAVEM circuit while the other is “black level stretch”. SCAVEM stands for SCAn VElocity Modulation and is used to delay the scan voltage to compensate for the delay in large video signal transitions which are caused by the capacitance of the picture tube. Normally, this capaci- by about 25%. Wide Screen is used for showing 16:9 program material, while Movie Expand (right) is used tance causes blurring of black-to-white and white-to-black transitions and this is quite noticeable on captions, weath­ er maps and so on. This feature really does work and makes the picture so much sharper than on conventional sets. In fact, in my opinion, apart from the flicker reduction of this set, the SCAVEM circuit is the feature which makes the biggest contribution to the outstanding picture quality of this set. We are not so sure about the “black level stretch” feature. As with other sets on the market, the new Philips set has a picture tube with a black face which gives a much higher picture contrast and makes the picture much easier to see in brightly lit and sunny rooms. So compared with sets of seven or eight years ago, the pictures to fill the screen while showing movies which have been broadcast in letterbox format. August 1994  7 are watching movies that the sound system really comes into its own (all the bass included). The set is supplied with satellite speakers for the rear surround channels and also has audio outputs to drive external amplifiers. Nor is their any need to connect a centre channel speaker because the Philips set simulates a centre speaker with its “phantom” speaker setting, via the front speakers. Even if the movie you are watching does not have Dolby sound, you can have a very good surround effect by selecting “matrix” which includes acoustic delay for the rear speakers. Chassis design This photograph shows how Teletext pictures can be displayed in 4:3 format while you watch (& listen to) a large PIP image. Note that the barrel distortion of the picture is mainly due to the photographic technique & is not evident on the set. already have better blacks and better contrast range (ie, over the full range from white to black, with all the greys in between). What the “black level stretch” is supposed to do is to increase the picture contrast of the dark parts of the picture. As I understand it, it pushes the black level down towards the blanking level so that the blacks are “blacker than black”. In my opinion though, it merely makes the picture too dark. I was able to make a direct comparison between this set and another Philips set which is 9 years old. The older set revealed more detail in the greys of the picture, simply because they weren’t so black. In effect, the black level extension seems to compress the bottom of the grey scale so that dark greys become black. Picture preferences Being something of a “video hifi enthusiast” I believe there is only one setting of contrast, brightness and colour temperature (picture white) which gives the best overall picture. However, Philips has provided for a number of picture preferenc­es which are entitled Rich, Soft, Natural and Personal. In my opinion, the Rich picture is much to dark, the Soft picture is blurred and the Natural picture is not too far away from being right although it still loses detail in the dark greys. Thankful­ly, you can set up your own personal preference and when that it done, it is excellent. 8  Silicon Chip Similarly, you can chose your colour temperature for the white areas of the picture and these are given as Normal, Warm and Cool. Warm makes the whites look pink while Cool makes them look blue. Normal is correct. Sound preferences In line with the concept of viewer democracy, Philips give the viewer a whole bunch of sound preferences which are listed as Voice, Music, Theatre and Personal. For most programs, the Phil­ips set just gives too much bass. In fact, it has a superwoofer enclosure intended to boost the bass and it does that very effi­ciently. Consequently, in order to make the sound as intelligible as possible, it is necessary to cut the bass right back and this became my “personal” setting. All of these adjustments are done via on-screen menus which appear superimposed on the picture every time your press a relevant button on the remote control. Even setting the volume is done to the accompaniment of a bargraph on the screen. And that brings me to another minor criticism. The avail­able increments in the volume setting are too big, so much so that with the volume setting at half way, the sound is at bellowing level. This could be easily fixed with some run­ning changes to the software in the microprocessor’s ROM. Dolby surround sound Philips has full Dolby Pro-Logic decoding in this set and it is when you We’ve included a photo which shows the general setup of the chassis. Actually, there is no chassis as such but there is a large mother­board with quite a few vertical boards plugged into it. Interestingly, the set has its own error message system via an array of seven LEDs on the main board and these are driven by the microprocessor. These will no doubt help in fault diagnosis should service be necessary. Picture evaluation To come back to the main feature of this set, throughout our evaluation we were intrigued by the various wide picture modes, their effects and how they were achieved. According to one explanation we had from the Philips technical people in Australia, when you switch to the “Superwide” mode, the major area of the picture is undistorted although it is magnified slightly, by about 10%; it is only the two vertical edges of the picture which are stretch­ed to fill the screen. The method used to stretch the picture is quite simple in theory; just vary the S-compensation applied to the picture tube yoke drive. Having been given the above explanation, we found it hard to understand. After all, it takes 52µs to scan one line on a normal picture and clearly the scanning voltages do have to be varied to provide the varying degrees of picture stretch. Note that the picture is also stretch­ ed vertically (although not as much as horizontally) in the Super­wide mode. This can cause a problem with pictures that have captions at the bottom of the screen or where the image is cropped at the top. To solve this problem, the When in Super-Wide mode, the 10% vertical expansion means that some of the top & bottom of the image will be lost & this can cause a problem with captions. The top image is in Super Wide mode, while the bottom image is in Movie Expand mode. We found Super Wide quite satisfying for 4:3 programs. remote control has two buttons to nudge the picture up or down by a small amount. This picture shift is brought into play by an additional deflection coil on the tube yoke. Thus, you can nudge the picture up to fully view the cap­tions or nudge it down if someone’s head is being scalped at the top of the screen. Other deflection trickery by the Philips set means that movies shown in “letter box” format can be expanded to fill the screen (which means that you lose the edges of the picture. To more precisely judge the effects of the various stretched picture modes, we took a series of off-screen photos displaying a crosshatch pattern provided by a TV pattern generator. Each mode is identified with an on- screen label such as NORMAL 4:3, SUPER­WIDE and so on. Note that the 4:3 screen photo has black strips on each side of the screen. We were also able to make direct comparisons between the Philips wide­screen set and a 9-year old Philips 63cm set (the KR683 chassis, one of the last Philips sets to be designed and manufactured in Australia). When these direct comparisons were made we noted the hori­zontal and vertical picture overscan present in the older set. This amounted to about 7% or 8% which does not sound like a lot but it is quite significant when you see a picture which is not overscanned. When you consider this factor, the amount of picture stretching in the SUPERWIDE mode is not as much as you might think. If you look at the 4:3 crosshatch picture you will see that it has 10 horizontal lines and 13 vertical lines while the SUPERWIDE picture has 9 horizontals and 12 verticals. Note that the squares are stretch­ed horizontally more than vertically. In fact, we judged that in SUPER­ WIDE mode, the horizontal stretch is about +25% while the vertical stretch is about 12%. Furthermore, the amount of horizontal stretch is pretty even across the screen. Having demonstrated the various picture modes, it occurred to us that if PIP was on the screen it would be stretched too. So we tried it. Guess what? The PIP stays virtually the same size and in the same position, regardless of which picture stretch mode is se­lected. This is very clever because it means that the synchronis­ing and sizing of the PIP image which is inserted into the main picture has to be digitally varied to suit the stretch mode! Having tried all the variations, we have to say that watch­ing normal programs in the Superwide format quickly become the norm. Even though there is some slight overall horizontal stretching of the image, it is hardly noticeable, particularly if you have been used to watching a conventional TV which is normal­ly overscanned more in the horizontal than vertical direction. The bigger image is simply more satisfying. And when applied to movies broadcast in “letter box” format, it also increases the satisfaction. All told, we were very impressed by this new wide format TV set from Philips. It contains a host of technological innovations which really do add to the viewing satisfaction. We certainly did not want to send the review set back! Such technology does not come cheaply although you have to admit that compared with any other consumer product, this set does have a lot to offer. It has a recommended retail price of $6299. An optional matching stand is also available. Finally, as an extra service, Philips will install, connect and tune the set in the new owner’s home and demonstrate most of the features. This home installation service will be available seven days a week and after hours, throughout Australia. Not only that, Philips will also remove all the packSC ing materials for recycling. August 1994  9