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Originally Posted by Geo
Hi J_P.
From what i know, i agree with you about the frequency of the calculator.
You wrote """""And further, the examiner circuit also picks up electronic noise from the air that is added to the calculator signal.
This electronic noise in the air is usually of a similar strength to the signal picked up from the calculator, and the noise remains even when you remove the calculator""""".
Can you explain me how the noise remains????
Regards  |
Hi Geo,
The noise is in the air, and can be measured if you set your oscilloscope to a sensitive enough setting. You can connect to a short length of wire like a coat hanger for an aerial, and walk around to see where the noise is stronger. The examiner has an aerial which acts to conduct most of the broadband noise in the air so the signal is a little stronger than if the probe is not connected to it. When we place the calculator on the Examiner, the noise coming from a calculator is slightly stronger than the broadband noise in the air because it is so close to the metal inside the Examiner. At a distance of about 1 cm the calculator noise can trigger an oscilloscope to follow any repetitive pulsing even with the broadband noise in the air competing to trigger the oscilloscope. But when you remove the calculator or turn it off, the broadband noise from the air remains, and still can be seen on an oscilloscope. Many of these noise signals from the air are also repetitive so you can lock their signal.
With the solar calculator, the the noise signal is weaker, and is not always stronger than the broadband noise in the air. I suppose it depends on what location you are measuring from. Keep in mind that when you are measuring calculator signals at these low levels, it can be easy to confuse some noise from the air with calculator noise. You will see a distorted wave form from the calculator because of the added noise from the air which makes it hard to know exactly what is coming from the calculator. So when you remove the calculator, you may begin to think that part of its signal is remaining, when it is not. This is why it might be good to put the probes directly on the calculator conductors to see a clear image of only the calculator signals. I have seen a lot of new noise in the air related to increased radio broadcasts, mobile phones, other high frequency transmissions, and new electronic equipment in homes which were not present in past decades. I suppose the cleanest areas for low background noise are very remote places far away from civilization. Maybe in the middle of a large desert, or at the north or south pole, or a deserted island in the pacific. In these locations, I expect man-made noise will be less, and natural electronic noises from the earth or space will be easier to detect.
See below for some clean measurements I made inside the Examiner TI solar calculator a year ago.
I am thinking I should make some more photos to show how these frequencies change when the light falling on the solar panel changes.
Do you think I should?
Best wishes,
J_P