band
I'm not sure that's correct. My Yaesu ("joy of ham's desiring") has a switchable antenna tuner and switchable RF stage, and they're not interlocked in any way. No engineer would design a ham transceiver that depended on an antenna to provide adequate selectivity.
Besides, the RF stage is also there to improve sensitivity (when needed). As for selectivity... image rejection is more-important than selectivity, and this is a triple-conversion receiver.
Whoops.
Jeff Liebermann Inscribed thus:
Good Grief ! If William started a search for "perpetual motion" he'd dissappear under a mountain of hits.
On 1/16/2011 3:38 AM William Sommerwerck spake thus:
[me said:]
Hint: I don't use smiley faces.
Of course math is essential to understanding electronics. I'm OK with algebra and trig, but have problems with calculus, even though I have a basic understanding of it (differentiation, integration, etc.).
Maybe in the next lifetime ...
"David Nebenzahl"
** Only one error.A basic superhet has two stages of filtering ( RF and IF) followed by one stage of detection.
** To shift the modulation down to base band - silly. ** Yep - that is exactly how it works.In the case of an AM receiver, the original carrier can be extracted and then mixed with the original AM signal to recover the modulation. Some hi-fi AM tuners worked this way.
** The you would be justifiably shot.Cos that describes a TRF receiver.
** Bob Dylan wrote a song about people like you...... Phil
"David Nebenzahl"
** Don't think DCR works with FM...... Phil
Hint: I don't generally assume they're there, unless I see them. As an extremely sarcastic person, I rarely fail to see sarcasm when it's present. Don't complain that I missed something that wasn't there.
Calculus is pretty simple -- if you have a good book. I can't recommend any, because I don't know any off the top of my head. (Recommendations, anyone?)
I took calculus in high school 45 years ago, at a time when very, very few high schools in the US offered it. We were given a book to study over the summer, which carefully walked the reader through the basics of the differential calculus. When we got to class in the fall, we a preliminary understanding under our belts.
You also need to learn about Laplace transforms. They make it possible to analyze circuits with simple algebra, rather than differential equations. Very, very handy.
Nah, plenty to read in this one :)
I wonder if you are aware of this collection of US Navy training manuals. Looks pretty well written, and only written 13 years ago so relatively recent.
On 1/16/2011 3:14 PM William Sommerwerck spake thus:
[I wrote, which for some reason William failed to attribute:]
I took one semester of calculus back in college and still have the textbook, a giant tome that's pretty good: /Calculus and Analytic Geometry/, Edwards and Penney. Didn't do too badly in the course, but that was a while ago ...
No doubt. Wouldn't hurt to know Fourier analysis either, and I'm sure a bunch of other techniques.
The Realistic TRF (12-655) radio was sold into the (IIRC) mid-80s:
TM
Fourier analysis is worth understanding on a theoretical level, but actually performing the analysis is something that's commonly left to computers.
lly
Thank God for computers!!
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