t;
>> Adrian
>>
>>
>> John Miles schrieb:
>>> That sounds about right to me. I was guessing you meant 40 dB and not 30 dB
>>> in the previous message, or there was something else causing about 10 dB of
>>> loss. Lots of things to go wrong
dB of
loss. Lots of things to go wrong in this process!
-- john, KE5FX
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
Behalf Of Adrian
Sent: Friday, May 07, 2010 10:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re
[mailto:time-nuts-boun...@febo.com]on
Behalf Of Adrian
Sent: Friday, May 07, 2010 10:38 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 11729C versus 11848A
Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor
at the input don't m
o:time-nuts-boun...@febo.com]on
> Behalf Of Adrian
> Sent: Friday, May 07, 2010 10:38 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] HP 11729C versus 11848A
>
>
> Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor
>
Just the roughly 16 dB of insertion loss caused by the 562 ohm resistor
at the input don't make that filter such a great solution ;-)
So, I brewed something better together...
The 10 kHz beat note is now near 0 dBm when the R input signal is
decreased by 40 dB, which makes a lot more sense than
John,
aside of having added the cal level reading wrongly (oops) which adds
some +6 dB to the (+10 dBm input level) noise floor and some +10 dB to
my 10811 readings, so they look a lot more reasonable, I haven't yet
checked the LPF filter response. The corrected 2x 10811 figures ar now
-150 a
> John,
>
> I'd say you nailed it.
>
> After some more testing, I can confirm that the limiter amp and the LPF
> are the culprit.
> I opened the box and plugged directly into the mixer LO port.
> And, for the LPF, as a quick 'n dirty solution, I connected the <1 MHz
> front panel output with the L
Sent: Friday, May 07, 2010 7:17 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 11729C versus 11848A
I don t have my notes here, but are these numbers
not for the 11729C system including the 8662A
rather than for the unit standalone? So as long
as you are mea
ime-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
>> Behalf Of Christophe Huygens
>> Sent: Friday, May 07, 2010 7:17 AM
>> To: Discussion of precise time and frequency measurement
>> Subject: Re: [time-nuts] HP 11729C versus 11848A
>>
>>
>> I
-LNA filter is job #1, IMO.
-- john, KE5FX
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on
> Behalf Of Christophe Huygens
> Sent: Friday, May 07, 2010 7:17 AM
> To: Discussion of precise time and frequency measurement
> Subjec
What the 10811 production line did was to compare two 10811's
to each other by driving a high level mixer. Anzac AM-123
amplifiers were used to increase the output level of the 10811's.
You can homebrew the AM-123 if you read the patent and can
get a 2N5109/2N5943 type of transistor. Amplify the
I don t have my notes here, but are these numbers
not for the 11729C system including the 8662A
rather than for the unit standalone? So as long
as you are measuring > 20-30 MHz the difference
848/729 should be much smaller than indicated,
or be attributed to the ref?
Xtof.
Adrian wrote:
> I tri
I tried to measure phase noise of a 10811A, but found out that the
specified PN is below the noise floor of my 11729C.
Can anyone tell why the (phase detector method) PN noise floor is so
much different between the two units?
11729C at 100 Hz -126 sBc/Hz (-133 dBc/Hz typ.)
11729C at 1 kHz -13
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