Questions tagged [high-frequency]
This tag marks questions related high frequency (radio) circuits.
0
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2answers
40 views
Passive Elements At high Frequency [parasitic effects]
What would the magnitude Response curve for a Resistor, Inductor and Capacitor look like [with parasitic effects not ideal components] ? From what I have gathered they would look something along the ...
0
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0answers
43 views
Resistors at High Frequency
[external R at 100]
[]1
1)Why is it that at high frequency the magnitude of impedance of a resistor (100) decreases?
2) At High frequencies a resistor would have a parasitic component of inductance ...
0
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0answers
40 views
Can this transitter on 319.5 MHz signal this receiver on 315 MHz?
In my pile of electronics pieces I have a wireless transmitter with this fcc id that supposedly transmits on 319.5 MHz. In the same pile of stuff I have a receiver with this fcc id that supposedly ...
1
vote
2answers
78 views
What's the role of Ground Plane in high frequency boards?
Here is an image of an LNB circuit:
As you can see there is some Vias that is pointless for me(blue circles). Why didn't the designer connect these components to the ground line around the circuit ...
1
vote
1answer
60 views
What's this length-tunned shape in this circuit?
Here is an image of an LNB circuit:
Probably you heard something about length-tunned traces that they use in high-frequencies PCBs. There is something similar to the length-tunned traces in the PCB(...
7
votes
1answer
1k views
Does it matter what size of via you use in high frequency circuits?
Here is an image of an LNB and there is some different "Via"s in the PCB that I don't know Why do they use different size of Vias in such circuits. Why? Any reason?
I showed two Vias using two arrows ...
6
votes
2answers
493 views
What do these parts of this PCB do?
Here is an image of an LNB circuit:
There is some parts in this circuit that I cannot know what they are. Marked them using blue circles. What are these parts and what do they do?
They looks like ...
0
votes
3answers
123 views
What's this component and how could these screws affect it?
Today, I was seeing the circuit of an LNB deeply and a part of it catched my attention. Here is an image of the circuit:
And here is two images of the bottom and the two components that catched my ...
0
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2answers
82 views
How to determine the current rating of Litz wire winding at high frequency?
How can we determine the current rating of a litz wire winding at high frequency?
This is my try:
For example, if we use 660/38 litz at 85kHz, we can see the equivalent AWG is 10 (reference). Then, ...
1
vote
3answers
95 views
High voltage to low voltage in ps/nanosecond time (Zener/opamp?)
So I have a signal that goes from 0 to ~800volts in 30ns. I would like to use this signal to trigger a camera (input impedance of 50ohm) which takes a max of 10 volts and requires the rise time to be ...
4
votes
1answer
99 views
Maximum via frequency
I am designing a 18 layer, 2.5mm board using the material FR408HR and I am wondering about maximum via frequency, because I should use them for PCIe 2.0 (5 Gbps).
I have not found a specific ...
2
votes
0answers
56 views
High frequency switching applications
I was reading that for high frequency switching applications with
semiconductors, the ratio of the electron to hole mobility should be high.
Why is it so? Is it a necessary condition always? Or ...
26
votes
8answers
6k views
Why is 50 Ω often chosen as the input impedance of antennas, whereas the free space impedance is 377 Ω?
In order to efficiently deliver power to a different part of a circuit without reflection, the impedances of all circuit elements need to be matched. Free space can be regarded as a further element, ...
45
votes
13answers
9k views
Why do fundamental circuit laws break down at high frequency AC?
We're just starting the whole RF scene having dealt with DC and low frequency AC for all our previous courses.
I understand that at high frequency AC, fundamental circuit laws don't apply anymore ...
-3
votes
2answers
151 views
Is there any way to convert 50 Hz directly to 1 MHz? [closed]
I want to know whether there are any ways to convert 50 Hz AC to 1 MHz without Voltage Controlled Oscillators?
If I'm correct, all the normal circuits convert the AC to DC and then use it to ...
1
vote
3answers
349 views
Is it possible to measure frequency upto 500Mhz with 50Mhz oscilloscope?
Is there a way to measure higher frequency measurements with a 50 MHz oscilloscope (eg rigol ds1054z)? Perhaps some post processing of captured waveforms? Or with the help of some adapters?
I have a ...
0
votes
2answers
96 views
Design a tank circuit for class C power amplifier using ADS
I am trying to figure out the best values for the tank circuit values (L and C) in order to compare the amplifier's efficiency with the output power
I have chosen the tank value L1 and C7 to resonate ...
0
votes
1answer
52 views
Impedance Matching Network with tracks+connectors in between (practice)
I've been struggling on how to design (and develop in practice) an impedance matching network with some traces/tracks/paths (whatever you wanna call it) and some connectors in between. So here is the ...
1
vote
0answers
85 views
Resonant, autotuned nanopulser
My need is to build (or purchase, if existent) a nanopulser, but not an ordinary one: it has to have some specific characteristics.
The premise is:
I have a device which acts as a variable capacitor ...
0
votes
2answers
65 views
High current/high voltage/high frequency measurement
I have a circuit that I'm having trouble understanding. It measures the current flowing through a conductor. The measured load is 20-100 Amps, 9kHz-34kHz, and approx. 340 volts. The main conductor ...
3
votes
2answers
202 views
How to amplify a low Amplitude, High frequency signal from Ultrasonic Transducer?
I am working with some ultrasonic transducers, the receiver gets a signal of around 10 mVp-p at 125 kHz and for its purpose needs a gain of around 10.
So far have a simple inverting OP-Amp setup, ...
0
votes
1answer
75 views
EHF RF Transmitter and Receiver
We are working on a blood glucose meter that will measure BG readings through radio waves with a frequency between 60-70 GHz.
That range is necessary to allow penetration through the tissue and we ...
0
votes
1answer
66 views
Asynchronous SRAM routing crosstalk concerns
I'm routing a large BGA SRAM that is connected to a BGA FPGA, and there's about 40 signals altogether connecting the two. I'm using Henry Ott's recommended 8-layer stackup:
1 ________________Mounting ...
1
vote
1answer
73 views
High voltage high speed low current amplifier
I want to design an amplifier that can take an 8MHz signal (even square) with an amplitude of only a few volts (1-3V) and amplify it up to 160V but I only need it to deliver about 60mA. I also want to ...
5
votes
4answers
2k views
Is there a small (6-pin) DIP I can use to generate multi-MHz squarewave clocks with an external crystal?
I'm building a circuit that I'd like to run at 8 MHz to begin with, but I want to be able to try it out at 10, 12, 16, 20, and, maybe, 25 MHz. I know that many microcontrollers have the ability to ...
5
votes
1answer
392 views
Build a High-Voltage High-Frequency Power Supply
I need to build a HV HF power supply to ionize gas. The specifications are 12V input voltage and 10kV output voltage @ 13.56MHz. I know this is not an easy task at all, since in this frequency area, ...
22
votes
3answers
2k views
Why solder mask are not applied to RF PCBs
I've gone through some of the RF PCB designs. In which solder masking on the traces are not present. Like this one
Is there a specific reason or performance issue to remove that?
0
votes
0answers
28 views
determine the cutoff frequency of a nMOS in common gate with gate resistance
I have to determine the upper cutoff frequency of this circuit.
I absolutely mustn't use the laplace domain because it's too time consuming so not compatible with the time I have at the exam.
A rapid ...
0
votes
2answers
76 views
Sram circuit design recommendations
I'm trying to design a simple SRAM board (using a cypress Cy7c1011cv33) to connect to my lattice machox3 starter kit's pin connectors. But I have some design questions, after reading their "SRAM Board ...
1
vote
2answers
109 views
High Speed Signal on Large Circular Ring
It's frequently communicated that when working with signals in the Ghz range, routing is extremely important to signal integrity. Pretty much any inclusion of unnecessary stubs is out of the question, ...
0
votes
2answers
81 views
High frequency AM demodulation
I'm building an light communication device(pretty much lifi) using AM and am mostly done with every part except for demodulating the signal. The signal looks like with a 1.8432MHz carrier wave(serial ...
2
votes
2answers
56 views
Radars and high frequency relation
Whenever I seach for radar implementations, independently of application (weather, military, autonomous vehicles, speed limiters, etc) it always comes in many flavours: huge antennas, small antennas, ...
-1
votes
1answer
127 views
Common source amplifier, source degeneration and determining the cutoff frequency
I have a n-MOS transistor with the following biasing network:
I have to determine the cutoff frequency due to GS and GD capacitances
The method used by my book is to first redefine the ...
0
votes
1answer
64 views
Multi-fixed-station AM receiver
I'm in the pencil-and-paper stage of building a radio receiver that has the following characteristics:
AM shortwave/HF
three fixed frequencies - 3.33, 7.85 and 14.67 MHz
single upper sideband with ...
0
votes
1answer
40 views
Problem with calculating high frequency response of a CE amp
I have this amp:
The parameters of the transistor are hfe=120, Cje=40pF and Cjc=4pF. I am also told to assume Cpi = Cje = 40pF and Cmu = Cjc= 4 pF.
From that I should calculate fh and compare it ...
0
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0answers
894 views
Smallest circuit for Ultrasonic Mist Maker or humidifier
I am working on Ultrasonic Mist Maker or humidifier circuit, but does not found any good circuit.
As search on google that we have to make about frequency 1.6MHz to convert water into mist. using ...
4
votes
1answer
387 views
How come esp8266 is able to generate 2.4 GHz wifi signals
I am wondering how it is possible to generate 2.4 GHz, if its core clock frequency is much lower than GHz scale.
0
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0answers
26 views
NMOS varactor Simulation Help?
I am trying to simulate a pair of NMOS transistors as varactors (BSD connected). However, am not getting any resonance at the particular frequency of interest. When I am simulating it, it is giving a ...
-1
votes
1answer
47 views
Are there any examples on the use of the frequency spectrum between 40 and 42 GHz? [closed]
Since everyone started talking about 5G, I got curious about some parts of the frequency spectrum.
I found out that some operators in the U.S. asked FCC if they could free the range between 40 and 42 ...
2
votes
1answer
85 views
Addition of HF Capacitor to Constant Current Source
The part of a circuit shown below was used in one of commercially sold audio amplifiers (constant current source shown here was added to differential amplifier, whereas voltage amplification stage ...
-2
votes
1answer
61 views
RF Antenna design guidelines, PCB design Antenna [closed]
What are the parameters to be taken care to RF Antenna designs and RF circuits designs?
What are the design criteria for RF designs?
-1
votes
1answer
173 views
What would be the maximum frequency that can be achieved with an LC Oscillator? [closed]
What would be the maximum frequency that can be achieved with an Oscillator that is based only on Capacitors and Inductors ?
Could it even reach high frequencies like Gigahertz or even Teraherz or are ...
3
votes
1answer
341 views
High voltage (2-6 kV), high frequency (20-50 kHz) power supply how to achive
I need to make a high voltage (2-6 kV), high frequency (20-50 kHz) power supply in order to generate cold plasma (in Ar gas). I use a fly back circuit (found in web) could allow me to to that. The ...
0
votes
0answers
36 views
Are there UHF RFID antennas with entirely different azimuth and elevation?
To improve UHF RFID reader's accuracy, I want antenna that has long, narrow reading field. So it needs to be directional and have vastly different azimuth and elevation. I stumbled upon few articles, ...
1
vote
2answers
94 views
Availability of 0.01 pF and 1 pF chip capacitor with SRF more than 15 GHz
I am working on a parasitic steerable phased array antenna, designed at 15 GHz. I need to terminate one of the array elements with a 0.01 pF chip capacitor to achieve desired steering direction. I ...
1
vote
1answer
714 views
high frequency transformer basics [closed]
What is the working principle of high frequency transformer??
Does it steps voltage or frequency and how it is different from ordinary transformers found in market?
P.S. I could not find proper ...
0
votes
3answers
208 views
Confusion regarding eddy current losses
I have been taught in my machine's class that eddy current losses are proportional to the square of frequency*flux density, this seemed so fair that I never questioned this. But my machine design book ...
2
votes
4answers
171 views
Fast (high) frequency hopping with off-the-shelf components
I am looking for the easiest solution to
synthesize 1.6 - 2.4 GHz (qudrature)
in steps of 4 MHz
settle within 10-50ns
precise timing control when to switch frequency (e.g., at rising edge of an ...
2
votes
1answer
160 views
Switching high voltage with consistent risetime
I'm trying to design an IEC61000-4-4 compliant EFT generator for in-house use, which is based on following schematic:
I've been able to determine all values for all components, And I've been able to ...
0
votes
3answers
211 views
High Frequency Rectification
I am trying to monitor an incoming signal and get some properties from it. The signal is a sine wave +-5V at 900Mhz. I am trying to measure the amplitude and the frequency of the signal. I will ...
