New answers tagged rf
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I need help understanding the envelope detector part
It's actually not that complex. When you take an average value of an AC signal of zero mean by low-pass filtering, the result is near zero.
By getting rid of the negative (or positive -- it doesn't ...
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I need help understanding the envelope detector part
It doesn't matter which polarity half of the modulated waveform you choose to rectify in order to detect the audio. It works just fine for both but, in the particular case of your circuit, the author ...
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MOSFET ring oscillator LT SPICE
Of course, you are not seeing any oscillations, as you use a default N/PMOS model, and this model is the Shichman-Hodges model, threshold-based model, which does not model device capacitances.
You can ...
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Demodulation of FM signal frequency
I researched on Internet and found useful materials. I managed to make a simulation in LTSpice. Here below is the circuit. I think it would work in reality, too.
The circuit works with 100MHz, ...
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Equivalent traditional transmission line of another with lossy return path
Without loss of generalization, the differential element can be written common-ground, with the total series resistance in the loop represented to one side, and the other as ideal ground.
That is,
...
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Design of 13.56MHz RF generator circuit for driving capacitively coupled plasma
For plasma ignition the two type of systems had been traditionally used. First was the vacuum tube circuits exploiting the parallel resonant tank. Thus tube having anode voltage 1000-1500 V but max 50 ...
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How do you chain 2-port S-parameters onto a 1-port S-parameter?
From Wikipedia (or pretty well any rf/microwave text covering S-parameters):
https://en.wikipedia.org/wiki/Scattering_parameters
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Why does this Gilbert cell configuration not have good local oscillator suppression?
With 170 and 100 MHz, you should get "only" 70 MHz and 270 MHz.
Why some others?
Something like this :
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Is it theoretically possible to make an anti-jammer for WiFi?
No, you cannot jam a jammer away. For two signals to cancel, they need to be perfectly 180° out of phase. But the phase changes with distance from both transmitters - so the only possible scenario ...
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Balanced vs differential signals
This is my view of the problem
According to the electromagnetic theory of guided TEM waves: the current flowing at the surface of the central conductor and that at the inner surface of the shielding ...
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How to make an 802.11b/g conducted power measurement, getting different results
I have asked some knowledgeable co-workers, and the answer they provided is as follows:
Amplitude vs. time is fine for measuring the peak conducted output power.
Integrated power (or channel power) ...
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Balanced vs differential signals
Here are some equivalent circuits you may find illustrative:
simulate this circuit – Schematic created using CircuitLab
Consider for sake of argument, the values of impedances don't matter, ...
- 27k
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Multiple Direct Digital Synthesizers (DDS) to Increase Sample Rate
Old thread, but the AD9166 can do what you want. It has a high speed DAC going up to 12 GS/s and the NCO can be digitally modulated with I/Q at several GS/s. So the data stream is not that much faster,...
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Taiwanese Regulations of 433 MHz
For the current document in English have a look here: https://www.ncc.gov.tw/english/files/12013/102_968_170120_1.pdf
All other links seem to be dead.
The relevant paragraph appears to be ...
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NFC antenna design - moving from rectangular to circular
Is it simply a case of creating a spiral with the same overall length
as the rectangle, with the same track size, spacing etc
No, it will be kind of luck if that manages to work out. You might get ...
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Fixing SMB adjustable contact to its SMB connector (Jack)
I contacted Radiall on this matter. Here is the response:
I see what you are saying about the word "adjustable". The TDS says
"adjusted", I think that it's a typo on the website. ...
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Matching network for a radio
Here is the datasheet for the IC
https://www.nordicsemi.com/-/media/Software-and-other-downloads/Product-Briefs/nRF52840-SoC-PB-23.pdf?la=en&hash=60847B0615FA41626CC73C9E5286C34F2481685E
General ...
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Matching network for a radio
It may be that the transmitter output impedance is low, but it'll usually be designed to drive a 50 ohm load through its specified matching network. Similarly, the receiver input impedance may not be ...
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3 dB Power Divider Used as Power Combiner S Matrix Explanation
The sum port of a Wilkinson is a superposition of the S-Matrix. Your answer is correct.
\$ [S] = {\frac {-j}{\sqrt {2}}}\begin{bmatrix}0 & 1 & 1 \\ 1 & 0 & 0 \\ 1 & 0 & 0 \end{...
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How do I calculate the hex value for the bandwidth setting on an SX126x?
I agree that hardcoding the table is the most appropriate way.
But for reference, the formula appears to be approximately:
Bits 0-2 of register value: exponent
Bits 3-4 of register value: divider
BW ...
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How do I calculate the hex value for the bandwidth setting on an SX126x?
It looks like I had to hard-code the BW setting(s). That's how they do it in the official library as well:
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Attenuation only at transmit without affecting receiver
Your phone doesn't work in the basement. Why? Either the closest cellular tower cannot generate strong enough field into your office or your phone has too weak transmitter to reach the tower through ...
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Impact of rain fade on 60 GHz radio links
There is a good summary of rain fade at 60 GHz here "Is There Rain Fade on 60 GHz Wireless Signals?"
This includes estimates of attenuation for various levels of rain:
Drizzle (.25 mm/h)...
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AM radio spectations - how does it work
That is your final amplifier. It is also your oscillator and modulator.
L1, C3, and C4 form a pi filter. However, they are also a positive feedback path, sending the emitter signal back to the base ...
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Frequency detector/comparator problem
There are a variety of frequency-to-voltage and voltage-to-frequency ICs, if you want to go down that route.
Another option, if you want to make such a system, would be to use the output of a non-...
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Frequency detector/comparator problem
NOTE: In your 2nd and 3rd schematics, components with the same reference designators have different values and do different functions. This is very confusing. Please update your post so the ...
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Why do amplifiers have minimum frequencies?
A while ago I played a little with SiGe transistors such as BFG425W and BFP650. I built some cascaded amplifiers and a noise source. The noise generator had about 5 stages of amplification.
I noticed ...
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Why do amplifiers have minimum frequencies?
Low frequency noise can become fatal to the high frequency noise performance if the low frequency signal is not prevented to be amplified. Low frequency noise can be strong in semiconductors when ...
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Why do amplifiers have minimum frequencies?
What would the impact of using a microwave LNA or PA on HF frequencies be?
If it's AC coupled, it has a low frequency cutoff.
Besides that, there's going to be filters and bias networks ; if the ...
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Understanding Parameters of Antennas
Antenna polarization can be described as horizontal, vertical or circular rotation (left and right). It doesn't really matter what transmitter frequency is chosen at the UHF frequency you have chosen, ...
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Implementing a light software stack on STM32 to send and receive data using 433Mhz RF modules
How do I generate the training preamble?
alternating 1 and 0. For 36 bit long sequence, generate:
010101010101010101010101010101010101
Do I have to do this for ...
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