In a message dated 19/06/2009 15:42:15 GMT Daylight Time,
optoma...@rogers.com writes:
I was thinking that if I
injected a signal with a known waveform I could follow it around the
amplification circuits and such. My only real need is to create
something that does not appear to already b
Patrick wrote:
Thanks John
With regard to frequency and price, low frequency is fine for me and I
am hoping to buy something for < $250-Patrick
The HP 3336 (A,B,C) is similar to the 3325 but somewhat lesser
capabilities and can be a bit cheaper. There is one on eBay "in working
condition"
Hi Patrick:
There are a bunch of signal sources that could be used.
The rack sized HP signal generators that weigh 50+ pounds were designed to have
very low phase noise and although now many years old are still very good for that.
The HP 3325() is the only signal generator that has adjustable
Robert Darlington wrote:
As John Miles said, no HP signal generator should produce a distorted output
at low level. My Tektronix does!
It depends on how they lower the signal level. If the signal level is
lowered using a traditional attenuator, the distortion will be unchanged,
but if the si
Patrick,
Using a large fixed attenuator should work fine. I learned the attenuator
trick when dealing with some variable gain amp chips from Analog. Instead
of varying the gain, they run at some fixed level that produces a clean
output, and vary the attenuation level to prevent non-linear effect
Patrick,
If signal tracing in a "mystery" circuit is important, I
would look for a generator with external FM input.
This feature is common in upscale units. Using a basic
audio function generator on the FM input, you can
supply 2 tone FM, switching at 1 or 2Hz which is
easy to identify in the
Hello Pat,
Ebay could be your friend in locating a signal generator, as well as
researching availability and pricing.
My perspective is that Ebay is the big flea market in the ether
and you do not know what you got, till you get it on your test bench
and exercise it.
Bid accordingly, most d
I took a look at the phase noise of a 3325B and as Jim said, the phase
noise is not great -- about -60 dBc at 1 Hz offset. An external
reference cleans up the close in (<10 Hz) signal, but beyond about 10 Hz
the synthesizer noice drowns out the reference; from the noise from 10
Hz to about 3 k
Hi James
Thanks for your feedback on this.
My needs are probably very privative compared to those of the people on
this list. I service a lot of the time without a schematic so I spend a
lot of time figuring out how the circuit works. I was thinking that if I
injected a signal with a known wa
On 6/19/09 6:38 AM, "optoma...@rogers.com" wrote:
> Hey Robert
>
> Great tip about the attenuator.
>
> I looked up some models on the internet and some look fairly expensive.
> I know that I will always be injecting low voltage signals, do you think
> it would be wise to buy a cheaper fixed
We use a lot of 3325As in the lab at JPL (they used to have dozens of them at
the deep space network, so there are lots of them around). Some have the rear
panel option that puts out a sine wave up to 60MHz, which is fairly convenient.
The settability with lots o' digits is nice (that's why they
How accurate?
What frequency range?
What spectral performance (harmonics, spurs)?
One thing to watch out for on testing with very low level signals is leakage
out of the signal generator and into the unit under test via a path other than
the coax. When we test deep space transponders at work at
9, 2009 6:39 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] OT favorite signal generator?
>
>
> Hey Robert
>
> Great tip about the attenuator.
>
> I looked up some models on the internet and some look fairly expensive.
> I know t
Hey Robert
Great tip about the attenuator.
I looked up some models on the internet and some look fairly expensive.
I know that I will always be injecting low voltage signals, do you think
it would be wise to buy a cheaper fixed attenuator, let's say 20dB?, and
then just depend on the variable
I just bought an HP 3325A synthesizer/function generator that I really like
(for some things anyway) in about that price range. What you get is
probably dependent on what YOU need though. This thing is pretty limited
but this particular one has the high voltage option so the output goes up to
40
Thanks John
With regard to frequency and price, low frequency is fine for me and I
am hoping to buy something for < $250-Patrick
John Miles wrote:
> Budget? Freq range?
>
> HP 8657As are good general-purpose SGs. Reliable, serviceable, and
> reasonably clean. Avoid 8656s and 8660s IMHO unless
Budget? Freq range?
HP 8657As are good general-purpose SGs. Reliable, serviceable, and
reasonably clean. Avoid 8656s and 8660s IMHO unless you can get one for
next to nothing.
If you don't mind getting your hands dirty there have been some inexpensive
8662As on the surplus market lately. They
Hey everyone
Sorry for the off topic post. I have received great advice in the past
with items for my little shop and I can't resist to ask again.
I am thinking about buying a signal generator. I suspect that I will
mostly use it to inject low uV/mV signals into the amplification stages
of the la
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