[time-nuts] Averaging effects

[Magnus Danielson]

Hej Bruce,

On 12/28/2010 03:43 AM, Bruce Griffiths wrote:
> Magnus Danielson wrote:
>> Actually, I ended up feeding a 10 kHz signal into the ARM1 input and
>> then let the 5 MHz sines hit the Ch1 and Ch2 inputs.
>>
>> The 5 MHz + 7 dBm sine signal has a limited slew-rate, so this puts
>> some extra stress on the inputs compared to a slew-rate optimized
>> signal. However, all the involved counters gets the same signal.
>>
> I found that a +13dBm signal gives far lower trigger jitter in my 5370A,
> even the effect of attenuating the input by 3dB is very noticeable.

To no big surprise. However, I cannot use that kind of signal level 
freely over the lab. I need to clip the signal or else I am in danger of 
burning up the inputs of the Wavecrests.

> Either add a buffer amp with a gain of about 6dB or use a pair of
> 2N3904s configured as an LTP diffamp with a gain of about 10 to increase
> the input slew rate.

Which is among the first things I would consider. Easy enough to cook up.

Cheers,
Magnus