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  1. E

    How to Convert uT to w/m2

    I believe frequency and wave form are related to signal density. That aside, what about the rest of my question?
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    How to Convert uT to w/m2

    I now recall seeing that 239 figure before. It is reflected in the attached chart where 960 W/m2 equals 1.0167 uT But, as you say, a static magnetic field and an EM signal per surface area are two different phenomena. However, they seem to be subject to correlation somehow. Possibly because EMR...
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    How to Convert uT to w/m2

    Is there any way to make a mathematical conversion between watts per square meter to Teslas? For example, if a 10mW/m2 RF signal was measured at a given surface, how can the magnetic component of the signal be quantified in micro Teslas?
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    Continuous Play from WTV020 SD Card Audio Module

    I can confirm the circuit in my previous post works, with the added benefit that the module starts playing on power up without the need to press a momentary button. Since "busy" is a high, the trigger to "next" needs to be converted to negative. Hence the transistor, a BC547. The values I used...
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    Continuous Play from WTV020 SD Card Audio Module

    Pin PO6 is a "busy". It is ordinarily connected to the cathode of an LED that causes the latter to be off when the module is playing and light up when it stops. I might be able to connect an NPN base to PO6. Emitter to earth. Collector goes to power and "next" pin, with a cap to earth to pull...
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    Continuous Play from WTV020 SD Card Audio Module

    Thank you for deciphering the "loop" explanation. It seems contradictory that the sequence would reset at the end but a trigger is required to cycle through the individual files. That implies that if there is only one file, as I have, it could be made to loop endlessly. What if I just keep the...
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    Continuous Play from WTV020 SD Card Audio Module

    I have a WTV020 SD card sound module loaded with a single 30 minute audio file that I would like to repeat-play continuously. Although the manual below describes a "loop" mode, I find the wording confusing. It sounds more like a resume after retriggering...
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    Load Driving from Transformer with Secondary Center Tap Earthed

    Yes. I got it backward.
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    Load Driving from Transformer with Secondary Center Tap Earthed

    Thank you. I will try this suggestion. Would it work equally well if I join the returns (low side) of the two resistive loads and the transformer's center tap at a single point and connect just one load resistor from there to signal ground? We used to say that "earth" was the US term for what...
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    Load Driving from Transformer with Secondary Center Tap Earthed

    I am feeding an audio signal into the primary of an 8 ohm to 1K ohm microphone coupling transformer. The secondary is split, having a center tap. I would connect the center tap directly to earth so I can pull inverted signals off the active legs and have each drive a small resistive load to...
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    Explain QPSK and ODFM

    In the context of 4G, can someone please tell me, in as simple terms as possible, how a QPSK signal modulates the OFDM sub-carriers? What form does an OFDM "symbol" take? I have read a lot online, but cannot visualize what the transmitted signal would look like.
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    Analog Circuit to Randomly Modulate Amplitude and Frequency

    That is a great source of circuits Bertus, and there is a ring modulator that uses the AD633. http://musicfromouterspace.com/index.php?MAINTAB=SYNTHDIY&VPW=1910&VPH=737 But the problem I am still having is not the modulation (multiplier). It is how to generate, or extract from noise, an extreme...
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    Analog Circuit to Randomly Modulate Amplitude and Frequency

    I built the part of the above circuit intended to produce a "random voltage". It all works fine until the low pass filter (U3d) which I assume is supposed to remove everything above about 30Hz and leave a slow random wave form. However, the output still looks very like pink noise. Can anyone...
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    Improvised Alternatives to a High Voltage Probe for Oscilloscope

    Mouser sells 100M 10KV resistors for about $4.50 each which should simplify construction a bit, assuming the input's HV distributed over a shorter distance does not encourage arcing. If so, perhaps I could seal them in a PVC tube filled with motor oil. Copper might be a better alternative to...
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    Improvised Alternatives to a High Voltage Probe for Oscilloscope

    Hmm ... I wonder why they call them negative ion generators? Anyway, my "modification" is just switching the HVDC output so it pulses at low frequency. Yes, this is observable via a neon bulb. Interesting point you made about only one electrode glowing. The original question was about...
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    Improvised Alternatives to a High Voltage Probe for Oscilloscope

    You implied the plate cap would not be charged by the HV source I described in my OP. I know from firsthand experience (as in "ouch") this is not the case. Thank you for taking the trouble to answer anyway. I was simply seeking expert practical advice on a specific problem. I understood that to...
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    Improvised Alternatives to a High Voltage Probe for Oscilloscope

    AC square waves are in effect pulsed DC. The frequencies involved are less than 100Hz, not HF. I want to set the cap up to charge and discharge at this rate by applying parallel bleed resistors. In other words, not simply charge up to 20KV and stay there. I can obtain some indication of this...
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    Improvised Alternatives to a High Voltage Probe for Oscilloscope

    I built a 20cm square plate capacitor using aluminum foil and an office laminating machine. It is being charged with a 20KVAC square wave from a modified domestic ion generator, which is a low current source. I would like to connect an oscilloscope across the plates to observe the waveform of...
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    Wi-Fi Beacon Photo or Plot?

    I have no practical application for this. I simply wanted to know, in general terms, how the beacon was integrated into the Wi-Fi physical layer. I thought a screenshot image might help. I would have liked to find one online, but could not. If I understand correctly, the beacon is a Wi-Fi...
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    Wi-Fi Beacon Photo or Plot?

    Here is a simple representation of what you accurately describe. It shows an "off" interval between beacons and data packets, and implies a difference in amplitude. From: https://www.cnrood.com/en/media/solutions/Wi-Fi_Overview_of_the_802.11_Physical_Layer.pdf
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