NBTV recording on paper tape.

[Stephen]

Reviewing the thread for recording NBTV on magnetic tape, it occurred to me that it might be possible to record and reproduce NBTV signals on rolls of paper tape. The paper tape rolls could be of the type for stock ticker or telex machines. A lateral disc recording head could serve as a recording transducer with a thin pen point replacing the stylus to record a line that shifts laterally in proportion to signal amplitude, much like a chart recorder. A photoelectric pickup could serve as a reproducing transducer to convert the proportion of white background to black line that is within its field of view to a variable amplitude signal.

The lateral amplitude of the recorded line would remain small so that the photoelectric detector would always see some white background in its field of view. In other words, the laterally modulated line would act like a variable area sound track in the motion picture art.

11/16 inch wide telex tape, in 1000 foot rolls, is still available. I came across one source online at http://www.wncsupply.com/paptape.html .

A magnetic disc recorder head is capable of response down to DC. So too is a photoelectric detector. Using telex tape rolls, it would be possible to record multiple "tracks" on each roll.

[DrZarkov]

It is possible to record it in that way. But how is the reproducing supposed to work? If it's just an alterning line, a photocell will not do it. That paper is quite expensive...

[Viewmaster]

Maybe an old reel to reel tape recorder transport mechanism could be adapted to transport the tape at 71/2 or prefereably 15 inches per sec past the recording head.
Albert.

[Stephen]

It is possible to record it in that way. But how is the reproducing supposed to work? If it's just an alterning line, a photocell will not do it. That paper is quite expensive...

Actually it would work fine if the view window of the photocell is of the proper size and follows along one side of the line. See the attached drawing.

A, B and C represent the view window of the photocell as the line passes by it at three different instances. The amount of light that the photocell sees changes with time because of the partial blockage of light due to a greater or lesser proportion of the line being within the area of its view window. This works just like the variable area modulation scheme for motion picture sound tracks.

With respect to cost, it seems that the cost of the 1000 foot rolls would be US$5.67 each in a case of 40. This is not too bad compared to some of the other recording media that we have suggested, such as recording discs and cylinders. Furthermore, it would be possible to record many tracks on the width of the 11/16 inch wide tape. As Albert has suggested, the 8 inch diameter of the rolls might allow the use of an old tape recorder transport mechanism.

If the recording mechanism has multiple recording and playback heads, different tracks could serve for video, audio and even synchronisation if desired.

[Viewmaster]

...And just think how very easy it would be to edit it..... Cut and paste!
NBTV out takes on the cutting room floor!
Albert.

[Stephen]

Another option with multiple recording and reproducing tracks is to have a simultaneous three colour system with individual red, green and blue tracks. Still another possibility is to record on a circular flat sheet of paper in a similar manner like a disc recorder. This would remove the expense of the paper tape rolls but possibly increase the complexity of the recorder/reproducer mechanism.

[M3DVQ]

Another option with multiple recording and reproducing tracks is to have a simultaneous three colour system with individual red, green and blue tracks. Still another possibility is to record on a circular flat sheet of paper in a similar manner like a disc recorder. This would remove the expense of the paper tape rolls but possibly increase the complexity of the recorder/reproducer mechanism.

a disc would only give a small amount of video, however how about a drum! the photo head could move along on a thread like the wax drum cutter head, this would give you a much longer playback. if using multiple heads for colour & sound etc. the speed of the tread would simply have to be greater, to make a steeper pitch of the lines drawn.

[Stephen]

a disc would only give a small amount of video, however how about a drum! the photo head could move along on a thread like the wax drum cutter head, this would give you a much longer playback. if using multiple heads for colour & sound etc. the speed of the tread would simply have to be greater, to make a steeper pitch of the lines drawn.

Yes, the cylinder approach would be technically superior as well because it would allow a constant track speed. With a drum of 6-2/3 cm diameter it would be possible to wrap a sheet of A4 size paper around it.

[Viewmaster]

......how about a paper roll of Andrex !
Albert.

[Stephen]

......how about a paper roll of Andrex !
Albert.

Good idea, Albert. Then even if all else fails, the contraption could serve as a distinctive tissue dispenser.

[Viewmaster]

The recording pen you suggested has to have a continue flow of ink and the modulation would have to be greater that the normal lateral excursion of a disc cutter head methinks. Old film had quite a big excursion to modulate fully the sound track on variable area don't forget.

Any grain in the paper media would also show up as noise.

We get some great ideas here for weirdie NBTVs, weirdie recording techniques etc but does any weirdie ever build 'em?

Albert.

[Stephen]

The recording pen you suggested has to have a continue flow of ink and the modulation would have to be greater that the normal lateral excursion of a disc cutter head methinks. Old film had quite a big excursion to modulate fully the sound track on variable area don't forget.

That is true. Perhaps what would be needed is some sort of ink jet coupled to the cutter head fulcrum. The cutter head would simply change the angle of the jet and then the amount of line displacement for a given angle would be proportional to the distance between the jet nozzle and the paper.

Any grain in the paper media would also show up as noise.

This is very true and I think that Andrex media would only be good for its intended purpose.

We get some great ideas here for weirdie NBTVs, weirdie recording techniques etc but does any weirdie ever build 'em?

Not me! I just try to stir the pot.

[Stephen]

Thinking further about Albert's suggestion of loo roll recording, it occurred to me that it would be possible with an ink jet and the proper absorbency paper to record using the equivalent of hill-and-dale recording. By increasing and decreasing the ink jet pressure, such as with a modulated pressure control valve, an ink line would change in thickness or cross sectional area with increasing and decreasing pressure. With the photodetector view window centred over the line, again the output would change like a variable area recording. In this case the only moving part would be the modulated pressure control valve spool or vane.

[DrZarkov]

That might work, the trace will look very similar to a optical sound trace on a movie. The problem is if you use ink and paper instead of film or photo-paper the paper has to move very fast to get a clear signal.

[Viewmaster]

Another problem (don't let this put you off building it though! ), is ink bleed and a fast drying ink requirement as the newly recorded ink paper is reeled into and onto the take up spool paper already there.

Assume a max modulation of say .015". An ink bleed of only 1 thou will then introduce bad distortion......
....Bleedin' distortion shall we call it !

Next design for a weirdo NBTV is an adapted musical box where the pin heights represents analogue output.
Now I'm weirdo enough to design an build my Edikow machine but not this one!

Albert.