What is this ? HP 7562A Log Voltmeter/Converter

[kagliostro]

A friend got this

http://www.testequipmentconnection.com/products/2691

we not only don't know how to use it but also don't know what it can do  

my friend is a radio amateur and give me that as in the instrument there is wrote "decibels"

so as he know I'm interested in audio frequency he give it to me as a present

Can you help ?

THANKS

Kagliostro

[jjasilli]

This should clear it up:  http://www.freepatentsonline.com/3657528.html   

[sluckey]

It's a linear (antilog) to log voltage converter. It has a range of 80db which is 10,000:1. Suppose you wanted to measure a voltage that could vary from 1 unit to 10,000 units. And you also want to plot the changes on a chart recorder (graph paper). Well, using a linear graph, would require at least 10,000 lines for an accurate plot. That's some big paper! But if you convert that voltage to a logarithm first, the change is only 80db. Now you can use graph paper with only 80 lines on it. Much more manageable.

The formula to convert linear voltage to log voltage is db=20log(E1/E2)

I doubt you will ever have a need for it. It needs to be in a laboratory along with chart recorders and other fancy scientist/engineer stuff.

Here's a link to a real world application and description of your converter. Look at pages 9-10 only.
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1968-10.pdf

[eleventeen]

Doubt if it's of any conceivable use to you.

I used to sell Tektronix & hp plotters....I'm not familiar with this piece, but it probably either converts raster graphics to vector graphics, which is what a plotter likes to see, or at least used to. OR, it converts linear to log scale so that you don't need a plotter the size of a skating rink.

Any conceivable program that contained a plotter driver would perform that conversion function in software vs in hardware; eg, an external box. So nobody else can use it either, which is comforting, LOL.

[kagliostro]

Many thanks to all friends for the answers

for sluckey

in the link you posted

http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1968-10.pdf

there is, at page 10, an example to use the 7565A with an oscilloscope to measure phase shift

I'm reading slowly the explanation because english is't my mother's language

do you think my (radio amateur) friend can use that instrument, I don't want withhold something I can't use and don't want to give the instrument to other people as I got it as a present, so, if my friend can use it in some way I would like to give it to him

Thanks again

Kagliostro

[sluckey]

I really doubt your radio friend could ever use this converter. However, send him the link to that pdf file and see what he thinks.

[kagliostro]

Done  

Thanks

Kagliostro