Ampex D-2 VPR-300 demo tape

Ampex demo of their "new" D-2 format VTR, the VPR-300. Interviews with industry leaders who have adopted this format talk about its strengths. D-2 was a great leap forward in video quality. Much better pictures than 1" Type "C", which was the current leading broadcast format at the time. It offered "read before write" or "pre-read" where you could insert over material already recorded on tape. It offered simultaneous playback and recording on the same VTR. D-2 was introduced in 1988. D-2 used 19 mm (¾ inch) metal particle tape. Need a dub from D-2 or D-3? Contact me.

Category:

Science & Technology

Tags:

• Ampex
• VPR-300
• D-2
• digital
• video
• tape

[Audiovideopark]

Ha. But how many ones and zeros? And at what rate? The bandwidth of a D-2 far exceeds an analog VTR, even a broadcast one. VHS was the worst NTSC consumer format ever invented. It has just enough bandwidth for two channels of digital audio. No digital video.

The data rate for D-2 is 143 Mpbs. D-1 is 270 Mbps.HDCAM SR is 440 Mbps.

[Celiecinema1]

@Audiovideopark A digital composite signal 143 Mbps? Do these things use ADCs and DACs? What is the voltage peak of a composite signal?

Sorry, I'm still an engineer in training.

[Audiovideopark]

@Celiecinema1 Yes, 13.5 MHz at 8 bits is common for the ADC using Y, R-Y, B-Y components for D-1. The composite video signal is one volt peak to peak. D-2 sampled from 140 to -40 IRE so it spread out the eight bits quite a bit. Some though too much.

[Celiecinema1]

@Audiovideopark Keep in mind that digital signals can be compressed.

[Audiovideopark]

@Celiecinema1 D-2 did not compress the video signal. Today, we have all sorts of compression but it is still just data and it depends on how much data you have that will determine where you can record it.

[Audiovideopark]

An analog VTR like VHS cannot record a digital signal. Besides, the D-2 bandwidth of 6 MHz is far greater than VHS at 2 MHz. No matter where you try to put the tracks, you don't have anywhere close to the bandwidth requited.

[Celiecinema1]

Just record the signals in parallel instead of series.

So you get all the bits at once.

[Celiecinema1]

How can a digital signal require more bandwidth than an analog signals? All it is is a bunch of ones and zeroes side by side.

[Celiecinema1]

Suppose digital composite (and L&R audio) signals were added to a standard VHS tape deeper than the Hi-Fi signals, but with all analog tracks so it would play in any VCR? It would have this quality.

[Audiovideopark]

Yes. Recently, I played a 15 year old tape and it played fine. Remember that format has a lot of correction. Besides using data shuffling and redundancy, there are extra bits for correction. You can even disconnect one video head (out of four) and the video still plays fine,