"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 1 May 2004 23:37:26 +0200) it happened "Frank
Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul
Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and
measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.

Why that?

I expect amplitudes to double or at least rise, after
removing a load. Just nitpicking


--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

On Sat, 1 May 2004 23:37:26 +0200, "Frank Bemelman"
wrote:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.

---
LOL!


--
John Fields

On a sunny day (Sat, 1 May 2004 23:37:26 +0200) it happened "Frank Bemelman"
wrote in
:

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.
Why that?

On Sat, 01 May 2004 17:03:26 GMT, Jan Panteltje
wrote:

On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

---
Without doing a conjugate match and accounting for the impedance of
the voltmeter and the load, the best he'll be able to do is _assume_
that what he measures is what he's really got.

--
John Fields

On Sat, 01 May 2004 17:03:26 GMT, Jan Panteltje
wrote:

On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

Or double, presumably. :-)
Well there you go; I knew there must be a more elegant solution to the
one I dreamed up which basically involved taking a spread of 10 carbon
resistors of from 10 - 1000 ohms and measuring the applied voltage
across each, then arriving at power transferred in each by V^2/R;
drawing a graph of the results and finding the point of maximum power
delivered.
--

The BBC: licenced at public expense to spread lies.

"Jan Panteltje" schreef in bericht
...
On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

If it is half, you've got a funny generator.

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

On Sat, 01 May 2004 17:03:26 GMT, Jan Panteltje
wrote:

On a sunny day (Sat, 01 May 2004 14:19:59 +0100) it happened Paul Burridge
wrote in
:

Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?

Load it with 50 Ohms, and measure output voltage, remove load and measure
again.
If it is half, it is 50, else do the math.

Or double, presumably. :-)
Well there you go; I knew there must be a more elegant solution to the
one I dreamed up which basically involved taking a spread of 10 carbon
resistors of from 10 - 1000 ohms and measuring the applied voltage
across each, then arriving at power transferred in each by V^2/R;
drawing a graph of the results and finding the point of maximum power
delivered.
--

The BBC: licenced at public expense to spread lies.

"Paul Burridge" wrote in message
...
Hi,

I have a spare RF signal generator that has an unmarked output from a
type of socket I've never seen before. What's the simplest way of
establishing its output impedance? I've had a few ideas but no doubt
someone out there will know of something better, since I always seem
to end up making unnecessary work for myself.
Any suggestions?


The generators are more of a voltage source. They will deliver their rated
output when loaded to the proper impedance. Load it with 50 ohms and see if
it gives the rated output. If not try 70 ohms, or another value. One of
the reasons for using a 6 db pad is that it helps isolate the impedance of
the generator and receiver.

On Sat, 1 May 2004 15:30:18 -0400, "Ralph Mowery"
wrote:

The generators are more of a voltage source. They will deliver their rated
output when loaded to the proper impedance. Load it with 50 ohms and see if
it gives the rated output. If not try 70 ohms, or another value. One of
the reasons for using a 6 db pad is that it helps isolate the impedance of
the generator and receiver.

My main sig gen states "output EMF using 6dB pad" next to the socket.
WTF is a "6dB pad"?
--

The BBC: licenced at public expense to spread lies.

On Sun, 02 May 2004 14:09:44 +0100, Paul Burridge
wrote:

On Sat, 1 May 2004 15:30:18 -0400, "Ralph Mowery"
wrote:

The generators are more of a voltage source. They will deliver their rated
output when loaded to the proper impedance. Load it with 50 ohms and see if
it gives the rated output. If not try 70 ohms, or another value. One of
the reasons for using a 6 db pad is that it helps isolate the impedance of
the generator and receiver.

My main sig gen states "output EMF using 6dB pad" next to the socket.
WTF is a "6dB pad"?

---
A 6dB attenuator.

--
John Fields