[Hammarlund] Re: Sweep Method for Alignment (explain?)

[James A. (Andy) Moorer]

You didn't say what IF bandwidth you were using when you tried sweeping it 
at 100ms, 1s and 10s.

The response of the IF filtering will be related to the bandwidth used - not 
to the center frequency of the IF train.
The IF could be 455 kHz, or 5 MHz or anything. If it has a bandwidth of, 
say, 1000 Hz, then it will take on the order of 1-2 ms to settle, and that 
time will be independent of the precise IF center frequency.

Your calculation would be correct if it had a 455 kHz bandwidth - but then 
it wouldn't be a very useful IF strip.

Set the bandwidth to 100 Hz and try your test again. You should see some 
difference.


James A. (Andy) Moorer
www.jamminpower.com



----- Original Message ----- 

>
> Regarding the merits of slower sweep speeds, I did a check today, 
> comparing the
> IF response curve when sweeping at 1ms, 100ms, 1s and 10s ... there was no
> discernible difference at all.
>
> Indeed, since the time constant of the IF must be around 1/455kHz i.e. 
> about
> 2 microseconds, the system must charge up in much less time than 1ms. So I 
> don't
> understand why ringing would be a problem - have I misunderstood?
>