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#41
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I have a HP 141 series device which is reasonable from the point of view of
strong signal handling. It is surprisingly easy to produce intermodulation effects at levels lower than you would expect. A "forest" of signals at -20 dBm will produce IM effects by the additive effect of all their amplitudes.(you could easily get this from a 40M dipole at night for example) In fact, my friend Rod Green has done an article for QEX on a "figure of merit" device to test receiver strong signal handling which consists of a "comb generator" with harmonics every 20 KHz, and a bandpass filter covering the band of interest - say 7.0 to 7.2 MHz. At a comb level of -20dBm most receivers will be overwhelmed. Richard If I were designing a spectrum analyzer for the electronic instrument market, I would shoot for at least meeting Hewlett-Packard Agilent or Rhode&Schwarz specifications...R&D budget willing. That's a bit steep for the hobbyist area. The problem is that real incoming signals and the analyser's spurious responses all look very much the same on the screen. When you can't trust what the analyser says, it becomes very hard to understand what's really going on. Sigh. A spectrum analyzer, almost ALL of them, is one of the easier instruments to characterize from the outside, using other instruments. Frequency span, logarithmic linearity, passband of the final IF are all relatively easy to determine from the outside. Len Anderson retired (from regular hours) electronic engineer person |
#43
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In article , says...
Postscript is about as open and standard a format as you will find. It was never intended for online document distribution, though. Postscript is for (obsolete) printers, and .PS files are an (obsolete) hack. ..PDF is designed from the ground up for online viewing, and it's less likely to require users to compile their own viewer application. Actually, neither .PS or .PDF is as nice as DjVu for onscreen viewing, but of the three, .PDF has by far the best shot at long-term archive survival. -- jm ------------------------------------------------------ http://www.qsl.net/ke5fx Note: My E-mail address has been altered to avoid spam ------------------------------------------------------ |
#44
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John Miles wrote:
In article , says... Postscript is about as open and standard a format as you will find. It was never intended for online document distribution, though. Postscript is for (obsolete) printers, and .PS files are an (obsolete) hack. Erm ... Not from where I stand, and work, and not for a lot of other computer professionals -- although I grant that few of them are Windows users. -- Mike Andrews Tired old sysadmin since 1964 |
#45
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John Miles wrote:
In article , says... Postscript is about as open and standard a format as you will find. It was never intended for online document distribution, though. Postscript is for (obsolete) printers, and .PS files are an (obsolete) hack. Erm ... Not from where I stand, and work, and not for a lot of other computer professionals -- although I grant that few of them are Windows users. -- Mike Andrews Tired old sysadmin since 1964 |
#46
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Mmm. Postscript documents. Real useful. NOT... I know the feeling. However, Paint Shop Pro 7 will read PS files these days. |
#47
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Mmm. Postscript documents. Real useful. NOT... I know the feeling. However, Paint Shop Pro 7 will read PS files these days. |
#48
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John Miles wrote:
Mmm. Postscript documents. Real useful. NOT... Sounds like an interesting variation on the project, but without documentation in a standard, open format, his audience is going to be limited. Postscript *IS* a standard, open format - perhaps moreso than most. Try ghostscript as a freeware implementation for viewing and/or printing the documents. -- Chris Cox, N0UK/G4JEC NIC Handle: CC345 UnitedHealthGroup, Inc., MN10-W116, UNIX Services & Consulting 6300 Olson Memorial Highway, Golden Valley, MN 55427 email: (work) (home) |
#49
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John Miles wrote:
Mmm. Postscript documents. Real useful. NOT... Sounds like an interesting variation on the project, but without documentation in a standard, open format, his audience is going to be limited. Postscript *IS* a standard, open format - perhaps moreso than most. Try ghostscript as a freeware implementation for viewing and/or printing the documents. -- Chris Cox, N0UK/G4JEC NIC Handle: CC345 UnitedHealthGroup, Inc., MN10-W116, UNIX Services & Consulting 6300 Olson Memorial Highway, Golden Valley, MN 55427 email: (work) (home) |
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