ticks from WWV (mosquitos give me more problems)
Leigh Palmer (palmer@sfu.ca)
Thu, 21 Aug 1997 08:42:47 -0700
I wrote:
>> Narrow-band filters seldom sharpen wide band material, like ticks.
to which Walter Nissen replied
>I am operating outside of my range of experience, but the "Time and
>Frequency User's Manual" seems pretty clear on this matter. "Tick" is
>apparently a euphemism, or approximation to the impression of the
>received sound. In fact, the manual actually uses the word tick with
>double quotes around it, "tick". Each WWV tick consists of 5 ms of
>1000 Hz (WWVH 1200 Hz, CHU 300 ms 1000 Hz). So, even if there is some
>spread, the received audio frequency of the signal should be highly
>concentrated in the region of 1000 Hz.
It would indeed, and a 1 kHz wide notch filter would transmit only the
envelope. I was a ham operator for about fifteen years*. The narrower
the filter band the more an AM voice signal sounds like it is coming
from someone down a well. Narrow band filters are very useful for CW
(code) reception where the relevant signal has much lower frequency
components. It still sounds like it's coming out of a well, but that's
the narrowing of the bandwidth of the background noise.
Leigh
*ages 15-30.