Forums

Frequency response of DFT single bin

Started by Jon Harris September 10, 2003
Jerry Avins wrote:
>
...
> see http://www.phy.ntnu.edu.tw/java/ruler/vernier.html >
The applet reads to the nearest .1 mm. In practice, .05 mm is easily estimated. Jerry -- Engineering is the art of making what you want from things you can get. �����������������������������������������������������������������������
allnor@tele.ntnu.no (Rune Allnor) wrote in message news:<f56893ae.0309120607.3aad6d3e@posting.google.com>...
> Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>... > > > Back in the old days, one used knobs, led's, and other archaic forms of > > user interface. One might have used some sort of digital encoder to > > select something like a frequency. Integers would have a nice smooth > > vernier control as you hunt for a specific frequency. > > At the chance of displaying my ignorance, what is a "vernier control"? > I have seen the term once or twice before and I can't find it in my > dictionary. > > Rune
After the French mathematician Pierre Vernier. Before digital calipers and dial calipers, there were Vernier calipers. The lowest significant digit of the measurement was determined by matching a scale marked with ten increments against one where the same distance was marked with nine. It gave pretty fine precision in its day. The term Vernier later came to mean anything with fine adjustment, so a Vernier control had two knobs: one for course adjustment, and one for fine. Glenn Dixon
Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjsq29$90j$1@newslocal.mitre.org>...
> Rune Allnor wrote: > > Stan Pawlukiewicz <stanp@nospam_mitre.org> wrote in message news:<bjo33t$a04$1@newslocal.mitre.org>... > > > > > >>Back in the old days, one used knobs, led's, and other archaic forms of > >>user interface. One might have used some sort of digital encoder to > >>select something like a frequency. Integers would have a nice smooth > >>vernier control as you hunt for a specific frequency. > > > > > > At the chance of displaying my ignorance, what is a "vernier control"? > > I have seen the term once or twice before and I can't find it in my > > dictionary. > > > > Rune > My apologies. > > In the part of the woods I grew up, central Connecticut (high school > shop had more stuff than UCONN's), the knob on a micrometer was called > often called a vernier, some called the focus knob on telescope eye > piece a vernier. The term was loosely applied to many fine scaled > adjustment knobs on machines and instruments.
Thanks. I knew of that sliding fine-scale-measurement thing Jerry pointed to (funny how all those *useful* words in a foreign language eludes you, even after practicing it for decades...), but I wasn't aware of the term itself, nor the generalization. Rune
On Fri, 12 Sep 2003 12:40:21 -0400, Jerry Avins <jya@ieee.org> wrote:

>Jerry Avins wrote: >> > ... > >> see http://www.phy.ntnu.edu.tw/java/ruler/vernier.html >> >The applet reads to the nearest .1 mm. In practice, .05 mm is easily >estimated. > >Jerry
I have an el-cheap-o Vernier caliper in the garage that I've been using over the summer to build parts for the track car. I've been corroborating through email with some other people so that we can pool parts orders, etc. We had a snafu in some unexpected deviations in part sizes from car to car, and I measured mine with the Vernier calipers, duly noting inches, tenths, and hundredths and reporting them to my colleagues (since I was the first to encounter the problem). I usually use the metric side of it, but in this case we were ordering sleeves that were only specified in inches. It turned out that what I had thought was inches, tenths, and hundredths, was really inches, eighths, and 64ths (or something like that). It was really aggravating, although completely my fault. They're a little tough on the eyeballs, too. Since then I've sprung the $$ for a nice digital caliper, so that I am far less apt to make such errors and suffer the combined scorn of my unforgiving associates. ;) Eric Jacobsen Minister of Algorithms, Intel Corp. My opinions may not be Intel's opinions. http://www.ericjacobsen.org
Rune Allnor wrote:
>
...
> > Thanks. I knew of that sliding fine-scale-measurement thing Jerry pointed > to (funny how all those *useful* words in a foreign language eludes you, > even after practicing it for decades...), but I wasn't aware of the term > itself, nor the generalization. > > Rune
Vernier is (almost) a French name. From http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Vernier.html : Pierre Vernier was taught mathematics and science by his father who was a lawyer and engineer who held government office. His father introduced Pierre to the works of Clavius and Brahe. Being born in Franche-Comt&#2013265929; (Free Country) meant that Vernier (and his father) were involved, not with the government of France but with that of Spain. Franche-Comt&#2013265929; was a Hapsburg possession controlled by the Spanish Hapsburgs throughout Vernier's life. In fact the period from 1598 to 1635 was one of peace. Vernier became a government official holding various positions such as military engineer for the Hapsburgs and director general of the treasury in Dole and Besan&#2013265927;on, the capital of Franche-Comt&#2013265929;. Vernier also held various government posts with the government of Spain and became a Conseiller du Roi. He worked for much of the time as an engineer, working on the fortifications of various cities. In 1623 he was given the title of citizen from the city of Besan&#2013265927;on for his work on the defenses of the city. In fact the threat of war was never far away and during the last two years of Vernier's life Franche-Comt&#2013265929; was frequently invaded by France. Like many other mathematicians and scientists of this period, Vernier worked on cartography and on surveying. He collaborated with his father in making a map of the Franche-Comt&#2013265929; area. His interest in surveying led to develop instruments for surveying and this prompted the invention for which he is remembered by all scientists. His most famous publication is La Construction, l'usage, et les propri&#2013265929;t&#2013265929;s du quadrant nouveau de math&#2013265929;matiques (1631). In this book Vernier gives a table of sines and a method for deriving the angles of a triangle if its sides are known. He also describes his most famous invention, that of the vernier caliper, an instrument for accurately measuring length. It has two graduated scales, a main scale like a ruler and a second scale, the vernier, that slides parallel to the main scale and enables readings to be made to a fraction of a division on the main scale. Article by: J J O'Connor and E F Robertson Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;
Eric Jacobsen wrote:
> > On Fri, 12 Sep 2003 12:40:21 -0400, Jerry Avins <jya@ieee.org> wrote: > > >Jerry Avins wrote: > >> > > ... > > > >> see http://www.phy.ntnu.edu.tw/java/ruler/vernier.html > >> > >The applet reads to the nearest .1 mm. In practice, .05 mm is easily > >estimated. > > > >Jerry > > I have an el-cheap-o Vernier caliper in the garage that I've been > using over the summer to build parts for the track car. I've been > corroborating through email with some other people so that we can pool > parts orders, etc. We had a snafu in some unexpected deviations in > part sizes from car to car, and I measured mine with the Vernier > calipers, duly noting inches, tenths, and hundredths and reporting > them to my colleagues (since I was the first to encounter the > problem). > > I usually use the metric side of it, but in this case we were ordering > sleeves that were only specified in inches. It turned out that what I > had thought was inches, tenths, and hundredths, was really inches, > eighths, and 64ths (or something like that). It was really > aggravating, although completely my fault. > > They're a little tough on the eyeballs, too. > > Since then I've sprung the $$ for a nice digital caliper, so that I am > far less apt to make such errors and suffer the combined scorn of my > unforgiving associates. ;) > > Eric Jacobsen > Minister of Algorithms, Intel Corp. > My opinions may not be Intel's opinions. > http://www.ericjacobsen.org
I have an old caliper that I got for a song at a flea market whose shape makes it useful for some things my newer ones won't fit. It too has an inch scale marked in sixteenths, and the vernier reads to 256ths. It's much harder to read than my "modern" one from Starrett that reads in 20ths and thousandths, interpolates to .0005. Like you, I mainly use the digital. I like being able do measure differences by setting any opening to be zero. It reads .0005, but I don't know how accurately. Mt one-nch screw micrometer reads to .0001 and interpolates to .00005. Except for optics and gyros, if differences like that matter, it's designed wrong! Jerry -- Engineering is the art of making what you want from things you can get. &#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;&#2013266095;