Fastest Chain East of the Rockies

[Gypo Logger]

Hi There, I am the proudest greenhorn East of the Rockies. My 385WXP is sportin a Martinized Carlton A1LM chain that requires sunglasses just look at. It chowed down on an 8x8 poplar cant in 1.16- 1.18 sec. I hope to reduce this to 1 sec. if I can modify the way I attack the wood. Our friend Ken Dunn was the timer of the cut via digital movie. I will make more cuts tomorrow and post results. Walts chain should arrive any time now.
Thanks to all.
John

 

[jokers]

"Real Time"

Hi John, just wanted give you words of encouragement about your times through the cut. As good a quality camera as you have, it is still highly likely that you aren`t getting a 100% "Real Time" playback. With the various electrical resitances present in all electrical components, compounded by one another no less, it`s very likely that timing your digital video isn`t optimistic. It will be some measure slower than your true performance in all likelyhood. High end electronics, from good hi-fi equipment to digital test equipment to space shuttle instrumentation, all consider this effect on the outcome of the finished product and provide compensation depending on the criticalitity of the application. Digital is better than analog, but not perfect. Keep up the great effort, Russ

 

[dbabcock]

Jokers,

I'm curious as to why you think that the digital camcorder would be inaccurate as far as timescale recording or playback. In this case, digital or analog makes little difference. When you record and therefore playback at the NTSC standard frame rate of just under 30 frames per second, this pretty much relegates a baseline timescale resolution of 1/30, or .033 second. That's as good and as bad as it gets. The digital clock or scanning signal reference has a far better resolution than this. In the end, to interface with your TV, sync signals have to be dead on and are accurate within millionths of a second at worst. While it's true that non linear editors used for processing the DV format in computers are capable of dropping frames, even the lowest end DV recorder has to maintain a frame-by-frame contiguous reference. From the recorder to it's LCD display or your TV is extremely accurate in realtime. It has to be just to function.

 

[jokers]

Interesting

Hi Doug, that`s more than I know specifically about DV cameras. My response is a general commentary on electronics and the typically indescernable, but existant, lag with real time. You are saying that it has to extreemely accurate just to work, well I can`t argue that because you obviosly know more about DVs than I do, but I do know there is a translation, and that can lead to error. That`s the long and the short of what I am saying. We don`t know what range of virtual perfection John`s camera runs in, I`m just saying that I think it`s a dubious way to time anything, unless all of John`s potential competitors were timed in exactly the same way with the exact equipment. Video is a great tool for examining technique, but I haven`t heard of any virtual competitions where all the competitors can just stay home and be digitally captured, and then sent to a central timing board, have you? If your right that DV is perfect, why are some video cards better than others for gaming or video editing? Oh yeah, and what if John`s camera battery isn`t quite up to snuff, isn`t there a standard voltage required to produce the video standard you cited with the hardware? Are we going to argue, or are you trying to shed light on this subject? Russ

 

[dbabcock]

Hey Russ,

No arguements ever from me on any forum. I know better. If I have knowlege about something and I can contribute in a positive fashion, I do. Since I know nothing about chainsaws and you guys do, I mostly read rather than write.

First, battery voltage. That's not an issue here as these things have internal regulators that keep the recorder running at some fixed lower voltage than the battery puts out. If the battery puts out say 7.2V, maybe the recorder needs 6V. The regulator is set to output a constant 6V and keeps the recorder happy as the battery voltage discharges from 7.2V to something under 6.5V, but above 6V (the regulator needs some voltage across it to work, this example sites a linear rather than a switchmode regulator). Once the battery voltage gets below a preset level, the camera stops working completely. Up until this point, the camera exhibits no ill timing or other effects, ie: it works 100%, then you get a low battery indicator and the camera shuts down shortly afterward.

Yes, there is absolute time delay in any electronic circuit. From the time the event happens to when it is recorded on tape is small, but it exists. The key here is to keep all appropriate signals, regardless of frequency and electrical path length, equal in relative delay. Once you do this, absolute delay doesn't matter at all.

You are correct in regard toward not using video for exact timing as per what I said before in regard toward the 1/30 or a second minimum resolution. In one frame, the saw chain is in the wood and the very next frame it isn't. That's .033 seconds of uncertainty, period. Not very accurate for timing situations that require precision down to .01 or even .001 second, but it will get you in the ballpark for informal use as in "1.16 to 1.18" second cut times. As far as the video of the cut went, assuming that the error in the stopwatch actuation was accurate, one could confidently say that the cut took 1.17 +/- .043 seconds based on ones observation of the video. This takes into account the initial +/-.01 second variance and a +/- .033 second potential maximum video frame time resolution.

Video boards in computers are different animals. Much of what makes some video cards better than others involves their ability to better process the graphics required for more realistic presentation of animated video. This is far more difficult than what is required for full motion real video. We're all used to TV. TV is a walk in the park compared to what computers have to do when it comes to animation.

Video is very limited in timing accuracy, but film on the other hand is much better. Standard motion picture cameras run at 24 frames per second (less than video), the faster you run the film, the more sensitive it has to be to light. The Imacon motion camera runs at 300 million frames per second giving it a native time resolution of a little over 3 billionths of a second (light and electricity would travel about 3 feet in this time span).

Well, I've wasted enough of this board's time with my babbling about electronics. Hope I've made this clearer rather than muddier. Sorry for the verbosity. Back to chainsaws.

 

[jokers]

Very Interesting

Thanks Doug, for the info. I had to read it twice to absorb it! So I guess you`re either in the electronics field or video, or both? I`m sure you just hit the "tips" here, but I think you did a good job in explaining to a level of detail which is apropriate. Russ

 

[rupedoggy]

Doug, If you will fix my computer I will fix your chainsaws! Mike

 

[dbabcock]

Thanks Russ,

Yeah, I design integrated circuits for a living. My audio and video experience comes from more of a hobby perspective than any professional work. I have a couple of Canon Mini DV camcorders, the GL1 and the XL1 that I horse around with. I presently edit on a dual 1.4G Pentium under NT 4.0 using Canopus DV Rex RT NLE software and hardware. This computer is pretty much dedicated to video only as video will take most any computer to it's knees. Most of my colleagues at work do things like play chess and read novels in there spare time. I build things, fly, hydrofoil, drive and play destructo in the woods with my Kubota and chain saws.

Rupe,
Sorry; for some reason I never developed an interest in screwing around with computers, although everyone has I hard time believing that I don't. I just use them like you do.