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Gizmo

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Posted: 10:34pm 15 Jul 2025

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Now these would look cool in a retro project. Popped up on my ebay browsing this morning.

https://ebay.us/m/i6BZCK

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Grogster

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Posted: 05:30am 16 Jul 2025

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Interesting little thing.

I guess this is B/W only?

Smoke makes things work. When the smoke gets out, it stops!

greybeard
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Posted: 05:52am 16 Jul 2025

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Quote I guess this is B/W only?

We only had B/W in the olden days

Martin H.

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Posted: 06:45am 16 Jul 2025

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yes, there is only one video-input signal (CCIR), it would be interesting to see if this can be generated with a little electronics from the Picomite.
Would certainly be a nice solution for the PicoMac

Google Gemini about CCTR:

Quote
the levels for sync, black level, and video signal are precisely defined in the standards for analog video signals. They are a central component of the BAS (Baseband Video Signal) or FBAS (Color Baseband Video Signal), as these standards combine all the picture information, synchronization, and blanking into a single signal.

The exact levels can vary slightly depending on the standard (CCIR/PAL or NTSC), but the basic concept remains the same. Here are the typical definitions, based on the European CCIR standard (625 lines / 50 Hz), which often serves as a reference:

Reference Levels for CCIR (PAL-like)

The entire video range of the FBAS signal is typically 1 Volt peak-to-peak (Vpp) into a 75 Ohm impedance. This 1 Vpp range is divided into different sections:

Synchronization Pulse (Sync):

Level: The sync pulses (horizontal and vertical) are in the "blacker than black" region. Their level is typically -300 mV (millivolts) measured from the blanking level. In other words, if the blanking level is 0 V, the sync pulse drops to -300 mV.

Function: They mark the beginning of each line (horizontal sync) and each field (vertical sync) so that the receiver can correctly build the picture. Without them, the image would "roll" or "tear."

Blanking Level / Black Level (Schwarzschulter):

Definition: The blanking interval (consisting of the "front porch" before the sync pulse and "back porch" after the sync pulse) is the period in the signal where no picture information is transmitted. It is the reference level for pure black.

Level: The blanking level is defined at 0 mV (or 0 IRE in NTSC). This is the Blanking Level.

Function:

Blanking: During the blanking interval, the electron beam in the display (for CRT TVs) or the pixels (for modern displays) are dimmed to make the retrace lines (horizontal and vertical) invisible.

Black Reference: It provides the receiver with a stable reference for the black level, which the brightness control can calibrate against.

Color Burst: On the back porch, the color burst is transmitted in color signals. This is a short sine wave pulse with the exact frequency and phase of the color subcarrier. It synchronizes the color demodulator in the receiver.

Signal Level (Picture Information):

Level Range: The actual picture information range lies above the blanking level (0 mV).

Black: Lies at or very close to the blanking level (0 mV).

White (Peak White): The brightest point in the picture, which is a maximum of 700 mV above the blanking level.

Overall Range: This means the entire visible picture area extends from 0 mV (black) to 700 mV (white).

Brightness: The amplitude of the signal in this range directly correlates with the brightness of the picture: higher amplitude = brighter, lower amplitude = darker.

Color: In an FBAS signal, the color information (chrominance) is superimposed as a modulated subcarrier signal on this brightness (luminance) signal.

Summary of Levels for CCIR (PAL-like):

Sync Signal: -300 mV

Blanking / Black Level: 0 mV

White Level (maximum): +700 mV

Total Voltage (Peak-to-Peak): 1 Vpp (from -300 mV to +700 mV)

Levels for NTSC (System M)

While the structure is similar, NTSC (USA, Japan) often defines levels in IRE units (Institute of Radio Engineers) and has slight differences in millivolt values, as NTSC specifies a 7.5 IRE setup (pedestal) for black.

Sync Signal: -40 IRE (approx. -286 mV)

Black Level (Pedestal): 7.5 IRE (approx. +53.5 mV)

Blanking Level: 0 IRE (0 mV) - Note the difference from the black level in NTSC!

White Level (maximum): 100 IRE (approx. +714 mV)

Total Voltage (Peak-to-Peak): 140 IRE (approx. 1 Vpp from -286 mV to +714 mV, with picture content ranging from 53.5 mV to 714 mV)

Does This Correspond to the BAS/FBAS Standard?

Yes, absolutely. These level definitions are a core component of the BAS or FBAS standards. They are crucial for the interoperability of analog video equipment, from cameras and recorders to television sets. Only when these levels are adhered to can a receiver correctly interpret, synchronize, and convert the incoming signal into a stable, correct image.

Edited 2025-07-16 16:45 by Martin H.

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Mixtel90

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Posted: 07:15am 16 Jul 2025

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A 4" LCD is cheaper, lighter, easier to drive from a Pico, colour and less power-hungry. :)

I remember these sorts of things being used in "pocket" TVs...
.
Edited 2025-07-16 17:16 by Mixtel90

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

Martin H.

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Posted: 07:50am 16 Jul 2025

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Mixtel90 said I remember these sorts of things being used in "pocket" TVs...
.

yes, creepy

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Mixtel90

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Posted: 08:27am 16 Jul 2025

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I was working it out a while ago.

The first commercially available germanium transistor was the "WX-3347" point-contact type transistor introduced by the Westinghouse Electric Corporation in 1953, the year after I was born.

The silicon transistor became available in mid 1954. It was the Texas Instruments 900-905 series. They were over 100USD each.

It wasn't until 1961 before silicon transistors were faster than germanium. This was the Fairchild 2N709 (FT-1310) n-p-n device. It was the subject of one of the biggest semiconductor orders ever placed, when Cray placed an order for more than 10 million of them in 1964.

We've come a long way in my lifetime. :)

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

zeitfest
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Posted: 11:51am 16 Jul 2025

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Quote cool in a retro project

I have seen these in use, they were included in early door security intercoms.
Colour lcd's replaced them sadly enough.
Certainly cool ! Amazing how the distortion from the geometry was cancelled out
to a reasonable image.

Always wanted one... at the time there was also a vector graphics monitor with "Asteroids" running in vector graphics. I think it was called Vectrix, expensive.
I saw one running once, in a second hand shop.

Mixtel90

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Posted: 12:13pm 16 Jul 2025

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There seems to be a glut of these around, here in the UK too. They may very well be NOS from a doorphone systems manufacturer.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

Volhout
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Posted: 12:38pm 16 Jul 2025

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That must be factory remains of the Sinclair TV....
I wonder if they still work...

Sinclair TV

Volhout

PicomiteVGA PETSCII ROBOTS

Mixtel90

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Posted: 02:31pm 16 Jul 2025

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Nope. Not the TV80/FTV1 anyway. Different tube, and it used a fresnel lens over it to make the picture appear bigger. https://en.wikipedia.org/wiki/TV80

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

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