use of Khz for sample frequency
use of Khz for sample frequency
(OP)
It seems to me pretty common to hear frequencies of digital sampling described in khz.
Is that a correct term? Seems like if I wanted to be very precise it should be k-samples per second.
p.s. - I had to put the capital K in there as a joke... I now know from the other thread it's supposed to be khz (or kHz?). Also is there anyone that really thought I meant degree Kelvin hz? (didn't think so).
Is that a correct term? Seems like if I wanted to be very precise it should be k-samples per second.
p.s. - I had to put the capital K in there as a joke... I now know from the other thread it's supposed to be khz (or kHz?). Also is there anyone that really thought I meant degree Kelvin hz? (didn't think so).
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RE: use of Khz for sample frequency
I've once read that kHz can be replaced by the shorter kc (kilocycle), and the Hz by the longer cps. Anyone who can see the logic please explain.
RE: use of Khz for sample frequency
Hertz, Celcius, and a host of other scientific names were re-named in honor of scientific pioneers.
As far as logic, however;
When I was in grade school and high school, common wisdom was that electricity flowed from positive to negative. Later I was introduced to electron theory and taught that electricity flowwed from negative to positive. We had to use our left hands for the right hand rule to determine the polarity of a magnet. Then "conventional current flow" surfaced. This theory decreed that an electric current was an unknown and mysterious force that caused electrons to move in the oposite direction to make room for it. There was something about electricity being a movement of holes that caused the electrons to migrate in the opposite direction.
You will understand that I was no longer giving this subject my full attention.
I once endured a serious staff meeting where the subject of discussion was "What is the policy of this institution as to the direction of electricity? Shouldn't we all be teaching the same convention?" I couldn't believe it when the meeting broke up with no consensus being reached.
There seems to be general agreement about the direction of electron flow.
What is the direction of the flow of electricity?
Whatever makes you happy.
respectfully
RE: use of Khz for sample frequency
The (relatively) new S.I. unit of frequency is Hertz, abbreviated Hz, and the earlier unit of frequency is cycles per second, abbreviated cps. The two are interchangeable, save for maybe thirty years separating them.
In Europe you will probably get some blank looks from anyone under 30 years of age when discussing frequencies measured in cps. I'm not sure whether North America has officially adopted the S.I. unit of frequency - I suspect so, given the number of US and Canadian posters here and the very rare mention of the earlier unit of measurement.
Pete,
I'm pretty sure I was taught 'sampling frequency' when studying digital signal theory. Certainly the term 'Nyquist frequency' is widely used over here in the UK. For those non-electrical readers, the Nyquist frequency is the theoretical minimum sampling frequency at which a signal can be sampled and the signal then reconstructed from the samples. The theoretical ratio between the two frequencies is 2:1, although any practical system will sample at a higher rate in order to reproduce the sampled signal more accurately.
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I don't suffer from insanity. I enjoy it...
RE: use of Khz for sample frequency
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: use of Khz for sample frequency
Benta.
RE: use of Khz for sample frequency
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RE: use of Khz for sample frequency
RE: use of Khz for sample frequency
I guess that's better than DC...
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"It's the questions that drive us"
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RE: use of Khz for sample frequency
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RE: use of Khz for sample frequency
(1*ham/month) * (month/(28*day)) * (day/(24*hour)) * (hour/(3600*sec)) * (hz*sec) * (1E9*nanohz/hz)
= 413.3597884*ham*nanohz
I assumed that your wife's ham dinners are tied to a catamenial cycle. Although the significance of direct current in the context of ham is not clear.
waross - don't get me started on current flow... TOO LATE! I learned in high school current flow + to -. Then in the Navy special high intensity training from - to +. Then in college had to unlearn the Navy and go back to + to -. And yes after repeating until it was drummed into my brain I even had to unlearn Mary's Fuzzy Canteloupe. I agree with you whatever you're used to is good enough. As long as you agree with me, that is. I have come to prefer + to - on the basis the voltage is potential and stuff likes to go to lower potentials. Current flow from - to + kind of seems like water flowing uphill, even if it is electrons.
On the original post, I think Greg and benta were looking at it the same why I was. But it's probably not an important point to begin with. I like the idea of putting sample rate in front of it so even if I use kHz no-one can second guess my terminology.
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RE: use of Khz for sample frequency
RE: use of Khz for sample frequency
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RE: use of Khz for sample frequency
[12 hams/yr] * [yr/(8600hrs)] * [hr/3600sec] * [1E9Nanohz*sec] = 388 nanohz.
Either way, nanohz is a funny unit to apply. At first read it sounds like a computer clock frequency (nanohz seems to fit right in between mhz and ghz)
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RE: use of Khz for sample frequency
Neither of you checked your units.
If your ham frequency is 1/month:
month * (30.42 days/month)* (24 hours/day) * (3600 sec/hr)
gets you 1 ham / 2628288 seconds
or
1 ham / 2.628E15 nanoseconds
Take the reciprocal to get nanohz
3.80E-16 ham / nanosecond or a ham rate of 3.80E-16 nanohz
RE: use of Khz for sample frequency
No. nanohz = 1E-9 hz = 1E-9 sec^-1 which is not the same as sec^-10
"gets you 1 ham / 2628288 seconds
or
1 ham / 2.628E15 nanoseconds"
Sounds about right.
"Take the reciprocal to get nanohz
3.80E-16 ham / nanosecond or a ham rate of 3.80E-16 nanohz"
Why would we take the reciprocal of the period in nanoseconds to get nanohertz? Do I take the reciprocal of the period in milliseconds to get millihz? No,
3.80E-16 nanohz would be 3.80E-25hz. I think that would be once every few ice ages.
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RE: use of Khz for sample frequency
reciprocal of period in nanoseconds would be frequency in gigahz.
Now where did the word period come from? Oh, never mind.
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RE: use of Khz for sample frequency
What I really need is an Intent Checker... I'd bet I could make a fortune with that.
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