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Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne
From: |
David Bengtson |
Subject: |
Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne |
Date: |
Tue, 14 Jan 2003 22:45:01 -0500 |
On Tue, 14 Jan 2003 19:25:34 -0800, you wrote:
>On Tue, Jan 14, 2003 at 06:19:31PM -0500, Lisa Bengtson wrote:
>> >How is this different than a single stage supper-het? Isn't that just
>> >mixing down to base band? Is there something I'm missing?
>>
>> Nope, you are not missing a thing. It's the same as a single Stage
>> Super-het, with an IF of Zero. Typically, a Super-het has a final IF
>> that isn't at DC.
>
>Are you saying that most receivers detect at IF (f != 0) and not a base
>band (f == 0)? I was under the impression that most detectors did their
>thing at baseband and required a final down convert from IF.
I'm familiar with at least one type of FM detector that uses a LC tank
resonant at 470 kHz to FM demodulate a 455 kHz IF, used in cheap and
Dirty pagers. I suspect that there are other demodulator types that
can demodulate a non-zero IF, although I'm getting out of my knowledge
area at this point. My main worry has been getting a signal from the
GHz range down to a few 10's of Mhz, and then I wash my hands of it.
>
>> Super-Het's are pretty well understood at this point, people have been
>> hacking on them for 70 years. Direct Conversion and Undersampling have
>> some gotcha's that are not fully understood and publicized yet. That's
>> what makes them interesting.
>
>That's why we're talking about it. We're geeks; it's in our nature
>to try something exotic and not fully understood, if it looks like it
>may have promise. :)
It's all fun and games until you actually try to make one on schedule
and under a cost target. :-(
Dave
- Re: [Discuss-gnuradio] Welcome and brief update, (continued)
- Re: [Discuss-gnuradio] Welcome and brief update, John E. Perry, 2003/01/13
- Re: [Discuss-gnuradio] Welcome and brief update, Tanner Lovelace, 2003/01/13
- [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Tanner Lovelace, 2003/01/13
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Mark Smith, 2003/01/13
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, David Bengtson, 2003/01/13
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Mark Smith, 2003/01/14
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Lisa Bengtson, 2003/01/14
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Mark Smith, 2003/01/14
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne,
David Bengtson <=
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, warren, 2003/01/15
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, David Bengtson, 2003/01/15
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Crusty Curmudgeon, 2003/01/13
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Nick Waterman, 2003/01/13
- [Discuss-gnuradio] Re: Direct Conversion vs Superheterodyne, Ian Wraith, 2003/01/13
- Re: [Discuss-gnuradio] Re: Direct Conversion vs Superheterodyne, Nick Waterman, 2003/01/14
- Re: [Discuss-gnuradio] Direct Conversion vs Superheterodyne, Jim Smith, 2003/01/14
- Re: [Discuss-gnuradio] Radio questions welcomed, Eric Blossom, 2003/01/12
[Discuss-gnuradio] RF front end, Tanner Lovelace, 2003/01/10