600HZ tv, only getting 50HZ

Munster Magic

I bought a HDTV in Currys lately which is supposed to have a frame rate of 600HZ but when I click on info it only says I have 50HZ

Stupid question but do I have to have a Sky HD box to get the 600 HZ rate or do I just need to change the settings?

Solair

There's nothing wrong with your television.

Television signals are broadcast as either 50Hz progressive (full frame sent) or 25Hz interlaced where 1 field (every second line) is sent per cycle, giving you a full frame only 25 times per second, but you don't notice a flicker, because you're seeing every second line presented in each field.

A television that has a higher refresh rate simply flashes the image up several more times to make it seem like the image is less flickery.

In reality, because the source is always 50Hz you are still only really getting a 50Hz refresh rate, it's just tweaked in software on the tv to make it seem better.

The formats used are :

Best:
HD : 1080p (50Hz Europe / 60Hz US) (Mostly Blueray DVD sources, not widely used for broadcast yet)
HD : 1080i (25Hz Europe / 30Hz US) (Commonly used Euro broadcast HD e.g. Sky HD / UPC HD / SaorView HD etc)

Middle: (More commonly used in the US for HD!)
HD: 720p (50Hz Europe / 60Hz US)
HD: 720i (25Hz Europe /60Hz US)

Standard Def (Europe) (Former PAL/SECAM 625 countries)

576p (50Hz)
576i (25Hz) (Standard Euro Broadcast Digital)

US Standard Def (Former NTSC 525 countries)

480p (60Hz)
480i (30Hz) (Standard US broadcast digital)

The reason for the 50Hz vs 60Hz systems are quite simply that historically television tubes were synchronized to mains frequency to ensure they synchronized with the broadcast signal. This is no longer the case with modern TVs but, the convention remained standard even in digital formats weirdly!

European power 230V 50Hz - generators turn at 3000RPM
US power 120V 60Hz. - generators turn at 3600RPM.

The choices were totally arbitrary and just developed as two isolated systems from the very start of electrical distribution systems in the 1800s.

mossym

yup, the 50hz you are seeing is the refresh rate of the incoming signal, the 600hz is the refresh rate of your panel, inside your tv is an FRC(frame rate converter) which takes the 50hz and converts to 600Hz, basically by showing the same frame 12 times (it's not quite that due to video processing, but basically thats it)

Overheal

though some TVs will "upscale" by basically blending one frame into the next by installing several new fade/transition frames in between them. My Sharp Aquos does this to make basic TV broadcasts and DVDs look smoother than they ought to. You might be able to find a setting for this. Sometimes for movies though it's better to knock it into standard: most of the time if a movie is upscaled to stupid high framerate, it loses it's movie feel and seems more like a behind the scenes documentary. And think about what that does to War Films where they use lower shutter speeds for artistic reasons - upscaling tends to ruin that effect.

Dazzling D

There's no such thing as 600Hz - it's just marketing BS from the plasma companies. Plasma TVs are either 50 frames/pictures per second or 100. LED/LCD TVs can be 50/100/200 pictures per second. 100 and 200 pictures per second are using created pictures artificially created by the TV's picture processing engine.

600Hz plasma sets are no better for motion than a 100Hz LED/LCD set.

andy1249

There's no such thing as 600Hz ...

When it comes to plasma , this usually refers to the subfield drive , in that there would be something like 8 -10 scans per pixel/field for each screen refresh , so with a little bit of creative math , we have what are actual screen refreshes in terms of picture , usually 50 or 60 , multiplied by the subfield scans , which is 8/10 , and you have something like 10 x 60 to come up with a figure of 600hz.

So , technically speaking , it is 600hz ( a very loose definition of hertz by the way ..it should be called fps !) but also very misleading in that it most definitely is not the equivalent of 600 frames per second.

Having said that , from experience , there is no way an LCD or LED backlit LCD screen , approaches plasma in terms of smoothness of movement , which is why I'll be sticking with my plasma until OLED becomes affordable.

As for the signal type report on the TV , it just reports what is incoming on the line , which seldom exceeds 60hz. Any internal processing by the actual TV is never reported , so you wont ever see 600hz actually on the screen.

Dazzling D

Hz can be applied to anything that changes per second

Entry level plasma
50 original frames x 12 pulses of electricity to each phosphor (subfield) = 600

Mid & high end plasma
50 original frames with interpolation to give 100 frames x 6 pulses (subfield) = 600

Plasmas have always been capable of this but when LED started adding 200Hz they needed to change their marketing to compete. From my experience, LED motion handling has surpassed plasma motion handling in recent years but you'll always get supporters of each technology and each have their uses.

andy1249

Hz can be applied to anything that changes per second

Anything that "changes regularly in cycles" per second.

Hertz by definition is cycles per second.

You wouldnt apply it for example , to temperature , which may change per second but wouldnt be expressed in hertz.

With TV's , depending on the nature of content , the fps is not necessarily continuously periodic , the signal may be , but the content may not be.

Dazzling D

Yeah, I know, just wasn't going to bother looking for the dictionary definition.

Solair

For LED/LCD matrix displays, this really shouldn't make much difference anyway. The pixels probably don't even respond to being switched on/off at 600Hz.

Pixels are either on/off. If you are watching an MPEG 2/4 compressed source, i.e. all digital TV, then it does not redraw non-moving parts of the image.

So, basically you aren't really seeing a refresh rate at all.

They don't scan a screen with a gun like an old CRT, which is where refresh rates mattered.

All this stuff is becoming very confused and it is also being very deliberately confused by marketing bods in various hardware companies.

There's a lot of selling of snake oil!

Dazzling D

LED's would have a response time of around 5ms which is much slower than plasma but then they use frame interpolation, high rates of refresh and backlight blinking to compensate. Plasma response time is very quick but the refresh rate isn't demanding that level of response. I think both have reached a level of motion handling that most customers would be happy with but LED is the winner for me in other areas.