Happy New Year.
Boldog Uj Évet.BUÉK. as we say in Hungary.
Ernie.
HG5ED
-Original Message-
From: Mike Feher [EMAIL PROTECTED]
To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com
Sent: Tue, 1 Jan 2008 1:16 am
Subject: Re: [time-nuts]
On Dec 30, 2007, at 19:03, Grant Hodgson wrote:
Henk
Two things will dominate if you want such a low phase noise spec.:-
the
loaded Q of the oscillator circuit, and the flicker corner frequency
of the sustaining amplifier transistor. To get a high loaded Q you
need
a crystal with
Henk -
Did you try to measure the PN out of the oscillator directly without the
buffer amp (U1)? Also, what is the voltage from V1? Is it also 12V? HNY -
Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-Original Message-
From: [EMAIL PROTECTED]
On Jan 1, 2008, at 13:42, Mike Feher wrote:
Henk -
Did you try to measure the PN out of the oscillator directly
without the
buffer amp (U1)?
No, but I will do it. I have to find a way, the emitter follower is
not expected to drive 50 ohm.
Also, what is the voltage from V1? Is it also
The emitter follower should have a very low output impedance, so, I would
not be too concerned about it's driving capabilities. If you must have 50
ohms, well, then just connect a 47 ohm resistor after the 1 nf capacitor and
measure it there, without U1. The confusing thing about the ADR455 is
On Jan 1, 2008, at 14:13, Mike Feher wrote:
The emitter follower should have a very low output impedance, so, I
would
not be too concerned about it's driving capabilities. If you must
have 50
ohms, well, then just connect a 47 ohm resistor after the 1 nf
capacitor and
measure it
Yes, that is what I figured regarding the 12V. For me, it has more or less
been a rule of thumb, but, I think at 10 MHz the best you could do, due to Q
and transistor noise and gain, was about - 155 dBc/Hz at about 100 Hz from
the carrier. I do not recall from your earlier post what you are
For what it's worth, the Wenzel 5 and 10 MHz ULN oscillators are
generally considered to be about the lowest noise oscillators
commercially available. They really shine in their noise floor.
There's actually (at least) one 5MHz oscillator with a better 1Hz offset
spec -- the Oscilloquartz
Tom -
Nice data. It really confirms what I initially posted. Your measurements
were at 5 MHz, so, the expected number at 10 MHz would be 6 dB worse. The
-155 dBc/Hz number quoted by memory from me then was not that far of at all.
- Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
Ernie -
Boldog vajuk hogy a masik Magyar van iten. Of course what I tried to say was
Best of Everything in the New Year. You made it easier to just say Happy
New Year. Hope we stay in touch - 73 - Mike (Mihaly)
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
Tom -
Nice data. It really confirms what I initially posted. Your measurements
were at 5 MHz, so, the expected number at 10 MHz would be 6 dB worse. The
-155 dBc/Hz number quoted by memory from me then was not that far of at all.
- Mike
Hi Mike,
What's the math behind why an equivalently
BTW, I remember when I was on a program and the initial oscillator was
specified at 5 MHz. When we changed it to 10 MHz, all of the vendors wanted
a 6 dB allowance on PN. - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-Original Message-
From: [EMAIL
Tom -
Sorry - I am not smart enough to answer that, other than from the experience
I had with the vendors. - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-Original Message-
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On
Behalf Of Tom Van Baak
There isnt any; that's not a correct assertion for crystal oscillators in
the general case.
The math associated with multiplying or dividing a frequency is pretty
straightforward. If an input edge is N picoseconds late due to jitter, the
corresponding output edge is also going to be N
Hi Mike,
I knew that you are Hungarian origin from your name..I use to travel a lot
to the US when PANAM
was big, but not anymore. Working here in Frankfurt/M and going home to
Budapest very often.
Keep in touch Misi,
Cheers, Ernie.
-Original Message-
From: Mike
In the HP 10816 Rb frequency standard, we used a modified
10811 oscillator circuit. The oscillator and first buffer
amplifier transistor were the same, but the rest of the
buffer amplifier was replaced with a cascaded grounded
base buffer amplifier. We were able to get numbers comparable
to
Henk ten Pierick wrote:
Bruce,
1. Best wishes.
2. It has taken some time but here is the schematic.
Henk
Henk
The circuit diagram helps a lot.
1) Since the crystal current is 1mA the RF voltage across R2 (and the RF
at the input of the HC04) is 220mV rms (622mV pp).
This is a little low
Gentlemen-
Since I got it working several years ago, my HP-5060A
has a rather loud ~2KHz audible whine coming from it.
It seems to be a result of the switching power supply
in the A20 oven controller module.
Is it worth my efforts to try and fix the problem
or have others already found a
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