[AILtech] Re: [Test-Equipment] LF Ailtech 7514 and noise sorce

[Edward J White]

Hi John:
what does the Ailtech 75 and 7514 unit do. The way the write up reads 
the noise source  works a bandwidth of frequency's that goes into the 
DUT and the output than goes into the Ailtech 75 or 7514? Or do you use 
a mixer to convert the output of the DUT to 30 MHz which is the input to 
the Ailtech 75 or 7514.

What is the difference between the Ailtech 75 and 7514 how about the 
HP-8970 A &B do they work the same?

I am just trying to figure what I would need to test some rec amps for 
50 MHz to 10 GHz>
Any help will be great. Maybe I need to do more research on the internet 
or some where else.
Ed
WA3BZT

J Forster wrote:
> QTH.net  is a real PITA. It sends out HTML, but insists on plain text
> input. Hence this repost.
>
> ***********
>
> Basically, a noise meter uses a noise source that switches on and off at
> a slow rate (typically under a hundred Hz or so) with
> known noise output. The noise source is connected to the input of the
> DUT and the output of the DUT is measured. The
> difference between the outputs with the noise source on and off is used
> to compute the NF or Noise Temperature of the DUT.
>
> Noise sources are calibrated in dB ENR..  Excess Noise Ratio...  which
> is the ratio of the source's output to that of a 50 Ohm
> termination. The noise source must be calibrated over the range of
> frequencies used to test the device.
>
> Typically, the output of the DUT is mixed and converted to 30 MHz or
> some other IF frequency then the noise is measured.
>
> There is a Yahoo Group about, among other things, about AIL NF
> Instrumentation:
>
>  http://groups.yahoo.com/group/AILtech
>
> Best,
> -John
>
>
> Tod -MN wrote:
>
>    I have read the messages on this topic with some interest. I wonder
> if
>   someone could supply me with information about how one uses such a
> device.
>   Perhaps just point me to where I can get some insight as to how it is
> used
>   and what frequencies are the most likely to be of interest.
>
>   Thanks in advance for any information.
>
>   Tod, K0TO
>
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