Cheap Spectrum Analyzer
 

anybody know of anything?

something that runs on a laptop would be ideal

only needs to go up to 15 kHz

There's an app for that!

When I think of a spec analyzer, I think of this thing I use in my shop:

http://www.ptltest.com/images/HP8590L_000.jpg
(not my pic)


How is this a spec analyzer???
http://ecx.images-amazon.com/images/...500_AA300_.jpg

Looks more like a frequency counter to me.
Where are the coax inputs?!!

yeh, that that top pic will work - ship it to me and I'll send you a beer

Just to clarify, I want a gizmo with a microphone on it; the mic feeds into a box (or an interface to a computer) and it then does a process called a transform (I am partial to FFT, but hey - I grew up in Louisiana), and you see (and/or can record) little bars sticking up on the screen of your laptop or device.

Each bar is set along the x-axis at a certain frequency, and the ht. of the bar on the y-axis is the amplitude of that (really those) frequency.

Any "uber wiz bang" digital stereo receiver from the 80s would have one of those...

You probably want one a bit more critical than that, huh?

Google to the rescue??

True Audio: Audio Spectrum Analyzer and Loudspeaker Design Software

Windows 7 Vista XP 2000 NT Music Software: Spectrum Analyzers (Shareware Music Machine)

SpectraPLUS - Audio Spectrum Analyzer

Audio Spectrum Analysis and FFT Spectrum Analyzers

We talking oscilloscope?

I will ask. I was discussing the need for a sweep of my desktop hifi with a co-worker & he had something that was quick & simple.

Ian

a bit...

no, these are not oscilloscopes - that is a "time domain" instrument

thx, Ian - I will await your info!

I sold one of those on e-bay for $5k several years ago. That was something like 90% off the price new.

I hear ya. I was thinking that I use my HP8920 if I am on the bench, or Anritsu handheld if I am out chasing RF interference.

The best tools for the job are as follows IMO:

Smaart
SysTune
PRAXIS

They have further advantages over stand-alone units and other basic RTA PC programs in that they have FAR more features and have more than one "channel" for comparative analysis (great for comparing pre & post processing effects/response). I am sure there are more out there, but the above choices are among the best.

Also, I believe all of them have free demo/trial downloads as well.

does that 8590 say 9 kHz to 1.8 Ghz?

$7000 used?

This is more my speed. The brown truck brought this e-bay purchase to me today (the HP3325 func gen). Notice how stable the output is. I am reading up on fractional - N PLL frequency synthesizers.

Function generator, RMS meter and a piece of graph paper = poor mans network analyzer.

EDIT: I guess a spectrum analyzer would have a tunable bandpass filter.

http://forums.pelicanparts.com/uploa...1291271146.jpg

I'd really like to get an Anritsu unit, but cannot justify it in the budget.

I think that is the range of the 8590. That was just an internet pic I grabbed for illustration. My actual unit is an 8920 that scans 4k to 1g.

As for price, you can find them on ebay at fairly good prices.

If you can get a sampled waveform into XL there is a discrete Fourier transform that works pretty good.

Randy: My cohort suggested:

"You need an external interface (M-audio for example), a measurement mic (like the Behringer ECM8000 $54.99 on Amazon) and software. Free stuff like REW (Room EQ Wizard)"

Ian

thx much Ian - I'll do just that if the M-audio, etc. is cheap enuff.