[time-nuts] Re: DMTD and TICC with YimeLab question

[Erik Kaashoek]

All,
What would the SNR of the input to the TICC have to be to have a no 
noise in the zero crossing when the time has been stretched by a factor 1e6?
1e6 calculates to 120 dB, 1e17 to 320 dB
Is that a problem when cascading a DMTD and a TICC?
Erik.

On 25-11-2022 11:51, Tom Van Baak via time-nuts wrote:
> Skip,
>
> Most programming languages and computer software, including Stable32 
> and TimeLab, use an ascii computer form of scientific notation with an 
> E in it (lower case e is ok too). So 1 million is 1e6, or 1000e3 or 
> 1000000. 2048 is 2.048e3, and so on. If in doubt use Excel or Python 
> or a calculator app to compute 1000 × 1000 and it should show 1e6 or 
> 1.0e6 or maybe 1 × 10^6 or 1.00 × 10^6. So that's the off-by-ten 
> problem you are having. For a million write 1E6, not 10E6. What you 
> wrote, 10E6, is ten million.
>
> When you see the E, read it out loud as "times ten to the power". So 
> 1.23E6 is 1 point 2 3 times 10 to the power 6.
>
> I used to nudge members to correct their postings where E-format 
> scientific notation was misused, or Allan was misspelled Allen, or 
> when 10 MHz was written 10 mhz or 10 Mhz or 10 MHZ, or when ns was 
> spelled nS or nsec or nsecs, but that turned out to be a losing battle 
> over time. In many cases the meaning in context was clear even if what 
> was written was technically incorrect.
>
> On the TICC question, with a DMTD heterodyne factor of one million, 
> which is 1e6, and a resolution of 60 ps, which is 60e-12 or 6e-11 s, 
> the theoretical resolution is 6e-11 / 1e6 = 6e-17 s. You could also 
> call that 60 as (attosecond).
>
> /tvb
>
>
> On 11/24/2022 6:45 PM, Skip Withrow via time-nuts wrote:
>> I have a DMTD front end (based upon the William Wriley design) driving a
>> TAPR TICC and processing the data with TimeLab.  I just want to make 
>> sure
>> that I understand how all the pieces fit together and that my results 
>> are
>> correct.
>>
>> The input signals are at 10MHz and I am using a 10,000,010 Hz offset
>> oscillator.
>> This means that I am getting 10 readings per second and that the input
>> phase difference should be multiplied by 10E6 (one million).
>> So, if I feed the same signal into both inputs with one delayed 9ns the
>> TICC (operated in time difference mode) should give a reading of 
>> 9x10E-9 x
>> 10E6 = 9ms (9x10E-3).
>>
>> Now, to make TimeLab give rational results the TICC difference readings
>> have to be scaled by the DMTD front end multiplication factor (one
>> million).  So, in setting up TimeLab the TICC time difference 
>> readings need
>> to be multiplied by 10E-6.  But I think there is a notation problem 
>> here -
>> I represent numbers as
>> n.n x 10Ey  and I think the TimeLab representation is n.nEy (can anyone
>> confirm this?).  This makes things very easy to be off by a factor of 10
>> (the problem I think I am having).
>>
>> Also, the TICC has a resolution of about 60ps.When the DMTD front end is
>> factored in does this mean that the (theoretical) resolution is 60 x
>> 10E-18s?  I realize that the noise floor is MUCH higher than this.
>>
>> Thanks for any insights, or putting me on the right track.
>>
>> Skip Withrow
>>
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