How Do PAL And NTSC Really Work?

January 7, 2026 by Jenny List 38 Comments

Many projects on these pages do clever things with video. Whether it’s digital or analogue, it’s certain our community can push a humble microcontroller to the limit of its capability. But sometimes the terminology is a little casually applied, and in particular with video there’s an obvious example. We say “PAL”, or “NTSC” to refer to any composite video signal, and perhaps it’s time to delve beyond that into the colour systems those letters convey.

Know Your Sub-carriers From Your Sync Pulses

A close-up on a single line of composite video from a Raspberry Pi.

A video system of the type we’re used to is dot-sequential. It splits an image into pixels and transmits them sequentially, pixel by pixel and line by line. This is the same for an analogue video system as it is for many digital bitmap formats. In the case of a fully analogue TV system there is no individual pixel counting, instead the camera scans across each line in a continuous movement to generate an analogue waveform representing the intensity of light. If you add in a synchronisation pulse at the end of each line and another at the end of each frame you have a video signal.

But crucially it’s not a composite video signal, because it contains only luminance information. It’s a black-and-white image. The first broadcast TV systems as for example the British 405 line and American 525 line systems worked in exactly this way, with the addition of a separate carrier for their accompanying sound. Continue reading “How Do PAL And NTSC Really Work?” →

Pocket-sized Test Pattern Generator Helps Check Those CRTs

December 26, 2025 by Donald Papp 27 Comments

[Nicholas Murray]’s Composite Test Pattern Generator is a beautifully-made, palm-sized tool that uses an ESP32-based development board to output different test patterns in PAL/NTSC. If one is checking out old televisions or CRTs, firing up a test pattern can be a pretty handy way to see if the hardware is healthy or not.

The little white add-on you see attached to the yellow portion is a simple circuit (two resistors and an RCA jack) that allows the microcontroller to output a composite video signal. All one needs to do is power on the device, then press the large button to cycle through test patterns. A small switch on the side toggles between NTSC and PAL video formats. It’s adorable, and makes good use of the enclosures that came with the dev board and proto board.

In a pinch a hacker could use an original Raspberry Pi, because the original Pi notably included a composite video output. That feature made it trivial to output NTSC or PAL video to a compatible display. But [Nicholas]’s device has a number of significant advantages: it’s small, it’s fast, it has its own battery and integrated charger, and the little color screen mirroring the chosen test pattern is a great confirmation feature.

This is a slick little device, and it’s not [Nicholas]’s first test pattern generator. He also created a RP2040-based unit with a VGA connector, the code of which inspired a hacker’s home-grown test pattern generator that was used to service a vintage arcade machine.

The Miracle Of Color TV

December 18, 2025 by Al Williams 36 Comments

We’ve often said that some technological advancements seemed like alien technology for their time. Sometimes we look back and think something would be easy until we realize they didn’t have the tools we have today. One of the biggest examples of this is how, in the 1950s, engineers created a color image that still plays on a black-and-white set, with the color sets also able to receive the old signals. [Electromagnetic Videos] tells the tale. The video below simulates various video artifacts, so you not only learn about the details of NTSC video, but also see some of the discussed effects in real time.

Creating a black-and-white signal was already a big deal, with the video and sync presented in an analog AM signal with the sound superimposed with FM. People had demonstrated color earlier, but it wasn’t practical for several reasons. Sending, for example, separate red, blue, and green signals would require wider channels and more complex receivers, and would be incompatible with older sets.

Continue reading “The Miracle Of Color TV” →

Japan’s Forgotten Analog HDTV Standard Was Well Ahead Of Its Time

November 6, 2025 by Lewin Day 36 Comments

When we talk about HDTV, we’re typically talking about any one of a number of standards from when television made the paradigm switch from analog to digital transmission. At the dawn of the new millenium, high-definition TV was a step-change for the medium, perhaps the biggest leap forward since color transmissions began in the middle of the 20th century.

However, a higher-resolution television format did indeed exist well before the TV world went digital. Over in Japan, television engineers had developed an analog HD format that promised quality far beyond regular old NTSC and PAL transmissions. All this, decades before flat screens and digital TV were ever seen in consumer households!

Continue reading “Japan’s Forgotten Analog HDTV Standard Was Well Ahead Of Its Time” →

Hackaday Links: October 19, 2025

October 19, 2025 by Dan Maloney 5 Comments

After a quiet week in the news cycle, surveillance concern Flock jumped right back in with both feet, announcing a strategic partnership with Amazon’s Ring to integrate that company’s network of doorbell cameras into one all-seeing digital panopticon. Previously, we’d covered both Flock’s “UAVs as a service” model for combating retail theft from above, as well as the somewhat grassroots effort to fight back at the company’s wide-ranging network of license plate reader cameras. The Ring deal is not quite as “in your face” as drones chasing shoplifters, but it’s perhaps a bit more alarming, as it gives U.S. law enforcement agencies easy access to the Ring Community Request program directly through the Flock software that they (probably) already use.

Continue reading “Hackaday Links: October 19, 2025” →

The Long Strange Trip To US Color TV

March 21, 2024 by Al Williams 48 Comments

We are always fascinated when someone can take something and extend it in a clever way without changing the original thing. In the computer world, that’s old hat. New computers improve, but can usually run old software. In the real world, the addition of stereo to phonograph records and color to photography come to mind.

But there are few stories as strange or wide-ranging as the path to provide color TV. And it had to be done in a way that a color set could still get a black and white picture and black and white sets could still watch a color signal without color. You’d think there would be a “big bang” moment where color TV burst on the scene — no pun involving color burst intended. But there wasn’t. Instead, there was a long, twisted path with many competing interests and ideas to go from a world in black and white to one tinted with color phosphor.

Background

In 1928, Science and Invention magazine had plans for building a mechanical TV (although not color)

It is hard to imagine, but John Logie Baird transmitted color images as early as 1928 using a mechanical scanner. Bell Labs had a demonstration system, also mechanical, in 1929. Baird broadcast using his system in 1938. Even earlier, around 1900, there were attempts to create mechanical color image systems. Those systems were fickle or impractical, though.

Electronic scanning was the answer, but World War II froze most consumer electronics development. Baird showed an electronic color system in late 1944. However, it would be 1953 before NTSC (the National Television System Committee) adopted the standard color TV signal for the United States. It would be almost 20 years later before SECAM and PAL were standardized in other parts of the world.

Of course, these are all analog standards. The world’s gone digital now, but for nearly 50 years, analog color TV was the way people consumed TV in their homes. By 1941, NTSC produced a standard in the United States, but not for color TV. TV adoption didn’t really take off until after the war. But by 1950, the US had some 6 million TV sets.

This was both a plus — a large market — and a negative. No one wanted to obsolete those 6 million sets. Well, at least, the government regulators and consumers didn’t. But most color systems would be incompatible with those existing black and white sets. Continue reading “The Long Strange Trip To US Color TV” →

Bringing Back The CRT TV Experience In Software

November 18, 2023 by Donald Papp 44 Comments

Cathode-Retro is a collection of shaders and sample C++ code for reliving the glorious days when graphics were composite video signals displayed on a CRT screen. How? By faking it in software and providing more configuration options than any authentic setup ever had.

Love it or don’t, there’s nothing quite like it.

Not satisfied with creating CRT-style color images with optional scanlines and TV picture controls like tint and saturation, Cathode-Retro can emulate more nuanced elements as well.

The tool includes the ability to imitate things like the slight distortion of a period-correct curved screen, the subtle effects of different methods CRT displays used to actually work (such as shadow mask vs aperture grille), and even taking into account the slight distortion of light refracting imperfectly through the glass face of the CRT. There’s even options for adding noise and ghosting, which may spark some artistic ideas.

If all you need is software to recreate an old-school CRT terminal, we have you covered. But if your needs are a bit more low-level, Cathode-Retro might be what you’re missing.