Hi all ,
I wish to know about the 10 MHz reference frequency.
Why is only the 10 MHz is used as the reference and not any other frequencies?
I hope if any one here can point out or suggest some notes for me to look at?
Rgds
Interesting point. Again, just guessing, but it may be like so many other things that a good reference point was picked for various practical reasons. The opposite that holds true and can be annoying with other things where nothing is standardized - computer operating systems for a long time were all over the place. Each brand had their own O.S. Finally through agreements, standard O.S.'s began to be used, The temperature scale, they picked the freezing point of water as the center point and built a scale around it and other ratiometrically related thermal points in nature. I would gues with 10 MHz frequency, perhaps Hewlett Packard for engineering or other practical reasons picked 10 MHz to be used to keep manufacturing costs down and to make a standard point to check for frequency accuracy (kind of in the middle of the frequency spectrum at the time). Even the Cesium beam began to be manufactured with a divider down from Cesium wavelength to 10 MHz - and everyone else followed suit. So now, frequency counters, signal generators, spectrum/network analyzerss, etc. are mostly all made using a 10 MHz reference point. It should be minorly noted that there are some products with other reference frequencies. I do some Tektronix AFG series function generators, I think, that have a 1 MHz reference frequency.
I've seen 1, 10 and 100MHz in various equipment over the years. I think it has to do with the preferred TCXO used in the instrument. This frequency is used to sync to or from more than comparing. Most precise time/frequency intercomparisions will use the phase difference of 1 pps over a period of days.
There are more that just 10 MHz ref frequencies out there. When we develop automated procedures for high end R&S hardware they have a test where we have to apply different frequencies to the Ref Input.
My take on the reason you don't typically see than 1MHz, 5MHz, and 10MHz ref frequencies has more to do with spectrum management and the break down of frequencies. These frequencies are usually in band breaks so they are not transmitted.
Mike.
we all asume that ruebenn was talking about Frequency counters, maybe he isn't. I seen many standard frequencies, I even seen some isntruments to use 60Hz (50Hz for European models) so ruebenn what kind of instruments are you refering with the 10Mhz signal?
Dear distinguished guests of the forum,
Thank you for the replies.
This question was actually asked by a someone while i was undergoing a training conducted by him.
Anyways, knowing that he is somehow connected to Agilent - i think he was referring to only Agilent products but then again, i see R&S, Advantest and also Anritsu using the 10 MHz reference instead of the other frequency references out there be it for frequency counters, microwave counters, signal generators and even receivers.
Anyways, thanks for the replies and i really think all replies hold some truth in it. Personally i think this is a rather general question and there could be more than one answer but i would take all the replies and try to incorporate them if ever i was asked this question?
Thank you so much