guhsd000@crash.cts.com (Paula Ferris) (02/13/88)
I play with eletronics as a hobby, I'm self taught (I know there's alot I don't know, but I'm not illiterate on the subject), and have never taken a formal course or class on the subject. <This is my excuse>
Anyway, I'm building some simple transmitters, from schematics. Anyway, it threw me a curve. I have never played with crystals, and there is something I don't understand. On the schematic it says:
"X1 - 52 Mhz, any 3'rd Overtone type"
And on a similar one it says:
"X1 - 16 Mhz, Fundamental"
What exactly is 3'rd Overtone type, and Fundamental? I know what an overtone is, but I'm not quite sure it's related here. I poured over by books, most of them don't disscuss crystals at all.
Can anyone help me out, and further my knowledge?
Thank You In Advance.
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======================================ron@topaz.rutgers.edu (Ron Natalie) (02/13/88)
High frequency oscillators frequently use crystals who would provide a lower fundimental frequency and use one of its harmonics. For example, back in my dim novice days (when novices were still required to use crystals) all my 15 meter (21 Mc) crystals were actually marked for somewhere around 7 Mc. The transmitter used the third harmonic (overtone) to generate the 21 Mc signal. -Ron Frequency is measured in cycles, not cubits, bushals or yards. Hertz rents cars.
keithe@tekgvs.TEK.COM (Keith Ericson) (02/18/88)
In article <18035@topaz.rutgers.edu> ron@topaz.rutgers.edu (Ron Natalie) writes: > >Frequency is measured in cycles, not cubits, bushals or yards. >Hertz rents cars. Hertz may rent cars, but frequency is measured in cycles PER SECOND! keith (MegaHertz: "She's-a no feel-a so goodt") ericson
phd@SPEECH1.CS.CMU.EDU (Paul Dietz) (02/18/88)
In article <3129@tekgvs.TEK.COM> keithe@tekgvs.UUCP (Keith Ericson) writes: >In article <18035@topaz.rutgers.edu> ron@topaz.rutgers.edu (Ron Natalie) writes: >> >>Frequency is measured in cycles, not cubits, bushals or yards. >>Hertz rents cars. > >Hertz may rent cars, but frequency is measured in cycles PER SECOND! According to Noah: hertz, n.; pl. hertz or hertz'es, [after Heinrich Hertz, G. physicist.] the international unit of frequency equal to one cycle per second. Using hertz rather than cycles per second is much like saying newtons rather than kg m / sec^2. 'nuff said? Paul H. Dietz ____ ____ Dept. of Electrical and Computer Engineering / oo \ <_<\\\ Carnegie Mellon University /| \/ |\ \\ \\ -------------------------------------------- | | ( ) | | | ||\\ "If God had meant for penguins to fly, -->--<-- / / |\\\ / he would have given them wings." _________^__^_________/ / / \\\\-
ron@topaz.rutgers.edu (Ron Natalie) (02/19/88)
It should be pointed out that due to successul "trying harder" by the #2 car rental firm, the units in question should be changed to MegaAvises -Ron
todd@uop.edu (Dr. Nethack) (02/21/88)
I have not followed this entire arguement, but as I recall, the cycles per second was replaced a few years back by Hertz in commemoration of Heinrich Hertz, an early radio pioneer. Has nothing to do with cars..
hes@ecsvax.UUCP (Henry Schaffer) (02/22/88)
Computing in Applied Science by William J. Thompson (1984) I've deleted the body of my review of this book which impinges on Computer Science, Mathematics and Science (particu- larly Physics.) ... but here is my concluding remarks - which I think are relevant to our recent discussion ... The only warning I have about this book concerns the author's taste in puns. I nearly cracked up at his suggestion that the major contributions of the electrical engineer C. P. Steinmetz (1865- 1923) be honored by using his initials for the unit of frequency. --henry schaffer n c state univ