[NSRCA-discussion] S.bus

Fri Jul 9 13:16:05 AKDT 2010

I don't disagree, but visual reaction is a big part of this.  Also I'd argue you're talking about the wrong side of the reaction.  It's not the time between seeing a problem and fixing it that we're thing about, but rather the time between fixing it (moving the stick) and having the plane react.  Latency and servo speed make up that delay.   I'm arguing that below about 15ms, it will be percieved as instantaneous.

Sent from my Verizon Wireless Phone

----- Reply message -----
From: "Phil Spelt" <chuenkan at comcast.net>
Date: Fri, Jul 9, 2010 4:49 pm
Subject: [NSRCA-discussion] S.bus
To: "General pattern discussion" <nsrca-discussion at lists.nsrca.org>

But,Mark, your movie analogy only considers the visual system -- each sense had its own throughput time, plus we must consider the "decision making" time between aircraft movement and then the later stick movement reacting to that aircraft movement...it gets very complicated very fast -- good thing we don't have to think through every little stick input before we make it.  It only takes about 2 or 3 seconds to "guide an aircraft into premature impact with terraine"...

At 01:28 PM 7/9/2010, you wrote:
Content-Language: en-US
Content-Type: multipart/alternative;
         boundary="_000_99B8EFCA36A5724F87FF3C71B431D87237DA4E49EAPEVM01paragon_"

It’s a good question, but I think the base number starts at zero.  Meaning we’re comparing NO latency with some latency.  I.e. 0 -11, or 0 – 14 or 0 – 250.    No delay is obviously the goal…though clearly impractical.   The question is at what point are we able to notice the latency.

I think the movie industry gives us a reasonable benchmark  to work with, in that movie frames are 30ms apart and we’re generally unable to discern any break.   There are faster systems for film that with studies are considered “smoother” but I believe below 15ms there was little perceivable difference (that was 72FPS if I recall)

Time to go do some research…or not.

Mark Atwood
Paragon Consulting, Inc.  |  President
5885 Landerbrook Drive Suite 130, Cleveland Ohio, 44124
Phone: 440.684.3101 x102  |  Fax: 440.684.3102
mark.atwood at paragon-inc.com<mailto:mark.atwood at paragon-inc.com>  |  www.paragon-inc.com<http://www.paragon-inc.com/>

From: nsrca-discussion-bounces at lists.nsrca.org [ mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Bill's Email
Sent: Friday, July 09, 2010 12:01 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] S.bus

The next question then becomes, at what level can we perceive a difference in performance? In other words, can we really perceive a difference between 7ms and 14ms latency? I will not argue that large differences are readily perceptible (25 versus 250), but what about smaller differences. How large of a difference does there need to be and is there a threshold below which it does not really matter?

Phil Spelt wrote:
As a Psychologist, I agree with you, Bill.  As an R/C pattern jockey, I will only point out that the electronic latency is ADDED TO the wet-ware latency...

Thus, your last statement is true, indeed!

At 11:19 AM 7/9/2010, you wrote:

I am amused by discussions about latency. We have long discussions about the perceived advantages of single digit differences in system latency while ignoring the fact that the average human reaction time (call it organic latency) is around 250 milliseconds.

I guess you can argue that since we are inherently so slow we need all the electronic help we can get!!

Jon Lowe wrote:

There is a great article on latency here:

http://www.rcmodelreviews.com/what_is_latency.shtml

A lot of people are hung up on transmitter/receiver latency numbers, and don't see the whole picture.  This gives as good a fact based write up as any I've seen.

Jon Lowe
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--> There are only two types of aircraft -- fighters and targets.

Phil Spelt, Past President, Knox County Radio Control Society, Inc.
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-->There are only two types of aircraft -- fighters and targets.

Phil Spelt, Past President, Knox County Radio Control Society, Inc.
       URL: http://www.kcrctn.com
<http://www.kcrctn.com/>AMA--1294,  Scientific Leader Member  SPA--177, Board Member
      My URL: http://mywebpages.comcast.net/~chuenkan/
      (865) 435-1476 v  (865) 604-0541 c