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 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 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.
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.
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.
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,
It so amazes me that most of this equipment is totally worthless today, and that control room alone must have cost 2 mill. The bank of machines must me 500k. Is there any use for any of this today?
But, on the other hand, audio recorders are going the other direction. Most people dont understand that I only SOURCE the audio on tape, the rest is edited digitally.
How does it react when you have video with off standard timing. For example when you have a yittery video signal from a colour under recorder? I mean you'd get a widely different number of samples per frame then.
sharing the D-2 and 1" type c formats with Sony didn't help them and Allied Signal selling Ampex to Ed Bramson and friends started the demise of Ampex. Now they sell solid state records used by boeing and the goverment. their last digital vtr was the DCT series.. a pitty sony took years to do it but finally put them out of the business they started
Yes, you are exactly right. Too bad that poor management and strong competition did them in. Remember that the president of Ampex was hired by Sony after he had been there for 25 years. I'm sure that helped Sony.
Ampex has some poor management but remember this company invented the first video recorder in 1956. A lot of history but had a hard time competing with the Asian manufacturers in the late 90s.
Yes. As the price of component digital came down, DigiBeta replaced the composite digital machines as well as 1". D2 was popular in the beginning because it was a fraction of the cost of component digital, especially items like switchers. D2 was less than half the cost of D1.
Since DVCAM has a luminance bandwidth of 5.75 MHz and has much less noise and is so much smaller plus is component, I'd take the DVCAM today. But the D2 wasn't compressed and you could go hundred's of generations. 50-60 was the most I ever used it for.
Yes, it is exactly the same. D2 is NTSC digitized. The advantage is perfect duplicates. With a D2 switcher, you could go unlimited generations. Even with an analog switcher, 10-15 generations was acceptable. It was the best way to record composite.
Too bad. I know of collectors that would like old video equipment. They restore and preserve the old gear. Please let me know before you throw away anything else.
I know how heavy those are. It takes at least four men to pick one up.
Just record the signals in parallel instead of series.
So you get all the bits at once.
Celiecinema1 3 weeks ago
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.
Audiovideopark 1 month ago
@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.
Celiecinema1 1 month ago
@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.
Audiovideopark 1 month ago
@Audiovideopark Keep in mind that digital signals can be compressed.
Celiecinema1 1 month ago
@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 1 month ago
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 1 month ago
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.
Audiovideopark 1 month ago
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.
Celiecinema1 1 month ago
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,
Audiovideopark 3 months ago
Has anyone ever played back a 19 year old D2 tape with no issues? Does the platform have good error correction?
shstrang98 3 months ago
It so amazes me that most of this equipment is totally worthless today, and that control room alone must have cost 2 mill. The bank of machines must me 500k. Is there any use for any of this today?
But, on the other hand, audio recorders are going the other direction. Most people dont understand that I only SOURCE the audio on tape, the rest is edited digitally.
analyzingfunny 1 year ago
I always use a time base corrector. That way the video is always clocked out at the correct frequency. The number of samples always stays the same.
Audiovideopark 1 year ago
How does it react when you have video with off standard timing. For example when you have a yittery video signal from a colour under recorder? I mean you'd get a widely different number of samples per frame then.
wrtlpfmpf 1 year ago
Sampling is 4x subcarrier.
Audiovideopark 1 year ago
If I may ask, is the sampling frequency locked to the colour subcarrier or the line frequency on those composite formats?
wrtlpfmpf 1 year ago
Do you have the link?
Audiovideopark 2 years ago
Here is a similar video that played at the sony booth about 1988.
OldProVidios 2 years ago
At 08:45 to 08:50 in this video i see a Yamaha M-85 power amplifier.
BoudjeR6 2 years ago
sharing the D-2 and 1" type c formats with Sony didn't help them and Allied Signal selling Ampex to Ed Bramson and friends started the demise of Ampex. Now they sell solid state records used by boeing and the goverment. their last digital vtr was the DCT series.. a pitty sony took years to do it but finally put them out of the business they started
ewalker3 2 years ago
Yes, you are exactly right. Too bad that poor management and strong competition did them in. Remember that the president of Ampex was hired by Sony after he had been there for 25 years. I'm sure that helped Sony.
Audiovideopark 2 years ago
Ampex has some poor management but remember this company invented the first video recorder in 1956. A lot of history but had a hard time competing with the Asian manufacturers in the late 90s.
Audiovideopark 2 years ago
And Digital Betacam killed this format.
bumtownv2 2 years ago
Yes. As the price of component digital came down, DigiBeta replaced the composite digital machines as well as 1". D2 was popular in the beginning because it was a fraction of the cost of component digital, especially items like switchers. D2 was less than half the cost of D1.
Audiovideopark 2 years ago
What was the bit rate of the format?
bumtownv2 2 years ago
D2 was an uncompressed format that digitized the composite waveform. The video sampling rate was 14.3 MHz at 8 bits. The data rate was 131.7 MB/sec.
Audiovideopark 2 years ago
So it's better than DVCAM. What ever happened to Ampex?
bumtownv2 2 years ago
Since DVCAM has a luminance bandwidth of 5.75 MHz and has much less noise and is so much smaller plus is component, I'd take the DVCAM today. But the D2 wasn't compressed and you could go hundred's of generations. 50-60 was the most I ever used it for.
Audiovideopark 2 years ago
I see, does digital composite suffer from dot crawl like analogue composite?
bumtownv2 2 years ago
Yes, it is exactly the same. D2 is NTSC digitized. The advantage is perfect duplicates. With a D2 switcher, you could go unlimited generations. Even with an analog switcher, 10-15 generations was acceptable. It was the best way to record composite.
Audiovideopark 2 years ago
Were promo tapes like this ever made for the VPR 1 inch machines?
Jarraknz 2 years ago
Could have been but I don't remember seeing any.
Audiovideopark 2 years ago
Too bad. I know of collectors that would like old video equipment. They restore and preserve the old gear. Please let me know before you throw away anything else.
I know how heavy those are. It takes at least four men to pick one up.
Audiovideopark 3 years ago
We just threw away a boat load of these
fndlair 3 years ago