Questions tagged [high-frequency]
This tag marks questions related high frequency (radio) circuits.
298
questions
0
votes
0answers
21 views
Conclusions about PFD/Charge pump simulation
I have built a Sequential NAND based phase detector with a charge pump that includes a differential amplifier and I want your help make some conclusions about the results I got running all the ...
0
votes
0answers
27 views
comparing between different phase detectors
I implemented two architectures of phase-frequency detectors and I'm interested to compare between them.
(I'm open for extra architectures that might solve problems that I'm not discussing here)
I'...
1
vote
2answers
87 views
Phase detection with non-ideal PFD
I'm trying to simulate for Phase Frequency Detector with the following implementation:
and inside NAND_PFD:
NOTE: the triangles on the right are inverters and not amplifiers.
I'm currently ...
3
votes
3answers
105 views
PCB design for 50MHz
I'm designing a rather big PCB which will have 64 nokia 5110 LCDs arranged in an 8x8 matrix and will all be controlled by a single microcontroller.
Each screen will have an 8-bit shift register as a ...
0
votes
1answer
39 views
Power devices max voltage, current, power, speed, etc. .. ratings
I want to know how to get the real world or the most recent or the reliable information about power devices max ratings in volt, ampere, power, speed .. etc., parameters.
I found this picture that is ...
0
votes
0answers
26 views
What is an equation that will show RF wave characteristics?
I want to show a RF wave on a spherical grid coordinate system. How can I show the RF wave when t = time and y = magnitude?
I also want to show curvilinear coordinate transitions of the RF wave ...
0
votes
0answers
46 views
Modulate/demodulate 125khz signal to 433Mhz transmitter module (2.5Ghz carrier)
I am trying to implement a project which consists of two circuits. Circuit A receives a 125khz AM signal and modulates it to 433Mhz CC1101 which then uses 2.4Ghz carrier to send at longer distance. ...
0
votes
1answer
25 views
Reduce Power of High frequency output signal (40khz)
I want to try and make the output power of the following driver board adjustable. At full power it runs at 100watt I. The board itself does not have an option to reduce the power output. The output ...
0
votes
1answer
55 views
Is isolation required for MOSfet gate driver's and microprocessor's power supply?
I have designed a 62W , 24V-5V buck converter operating at 250KHz.
I am using TI's UCC27200A gate driver and Infineon's Optimos 4.
The problem is that the driver doesn't have any kind of isolation ...
1
vote
1answer
65 views
Measuring the quality factor RLC circuit
I am trying to get the Q factor for this circuit but I don't know how to simulate it properly.
I did a frequency sweep from 1 Hz - 30 MHz.
The oscillating frequency is 16 MHz.
I can't get the ...
2
votes
0answers
29 views
Inverter Circuit using IR2113, TLC555 and signal inverter IC
Input DC = 30V
operating frequency = 10kHz
problem =
When I am at the no-load condition at the output, only the oscilloscope is connected, I am receiving the proper output. But when I connect a load,...
9
votes
4answers
2k views
Why does the cable resistance jump from a low value to high value at a particular frequency?
I am not well versed with transmission line theory so if you can redirect me to relevant material I'd be grateful. So I used Agilent 4294A to find resistance of a 2 metre long shielded twisted pair ...
0
votes
0answers
27 views
Decreasing phase noise of natural oscillators by passive resonant filter on-chip in the MHz regime
I was doing a literature research on microwave filters and to me it looks like passive SAW filters/resonators have the highest quality factor below 1.5 GHz, but with a high power loss. Coupled planar ...
0
votes
1answer
51 views
FR-4 RF attenuation (when used as an enclosure)
I want to use a blank PCB (no copper) as a panel of an enclosure because it seems to be the cheapest way (Seeedstudio et al.) to have custom holes and cutouts.
I wonder if antennas placed behind such ...
3
votes
1answer
64 views
High Voltage Planar Transformers
I am designing a high voltage DC/DC converter that is for an aerospace application and therefore I am focusing on reducing the size and weight, so switching at a high frequency possibly integrating ...
0
votes
0answers
60 views
Is the difference in trace lengths why my RTC isnt working?
I am using the PCF8523TS RTC with a 32.768 kHz Crystal. I have tested the smaller package which worked fine with the Adafruit module, but I can't seem to get it to work with the TS package. I either ...
0
votes
1answer
118 views
Brushless motor back and high current and IC
I'm trying to replace the brain of my neato vacuum which is broken.
I've already repair a cleaning MOP but with this one I have a problem with the brushless motor which is throwing some party fun in ...
2
votes
2answers
110 views
USB Routing: Switching layers during routing
I'm working on a standard 4 layer board that involves USB 3.0. I have to route the SS TX/RX pairs as well as D+/D- pairs across a 2.8" PCB. I have found multiple calculators that provide me the ...
0
votes
1answer
97 views
Power amplifier design
For my research purpose, I am planning to design one power amplifier (basically, a current amplifier) with the following specification-
Frequency range: 0-100MHz (or at least 0-30MHz)
Output voltage: ...
0
votes
4answers
162 views
Why can't all data be sent across 4 wires?
I am aware that USB uses a positive, negative and D+/- wires in order to transmit data. The twisted pair are used to negate the effects of interference and electronic noise.
I also understand that a ...
4
votes
1answer
867 views
Skin Effect of resistors
Skin effect of metallic conductors is well documented.
What about SMD resistors?
High values Vs low values? Above what frequencies would this be an issue?
3
votes
1answer
219 views
How are 200 GBit/s over twin-axial copper cable achieved?
The 200GBASE-CR4 standard [1] defines ethernet communication with 200 GBit/s using four lanes and PAM4 modulation over a maximum distance of 3 m.
A single PAM4 symbol encodes two bits, therefore, I ...
0
votes
0answers
135 views
How to create 113 kHz or 1.7 MHz AC signal for Ultrasonic Mist Maker?
I would like to control piezo disk for ultrasonic mist of variable frequency (kHz to MHz). Is it possible with a single circuit to generate different frequency depending on the type of disc that I use?...
2
votes
1answer
75 views
How to amplify a signal for piezo transducer from 1 Vpp to 200 Vpp at 400 kHz and 500 pF load
I'm a researcher working with phased ultrasonic transducer arrays.
I need to amplify a sine wave at 400 kHz and 1 Vpp to 200 Vpp. It has a capacitive load of 500 pF.
I'm little ...
1
vote
2answers
89 views
High frequency reduces power on circuit
I am not expert in electronics so there must be many errors that I am not considering. I designed a simple half wave rectifier that gives signal to a LDO voltage regulator of 3V3. In the input I have ...
1
vote
0answers
62 views
PHY Link only establishing 10 Mbps speed when both devices 100 Mbps capable
I've designed a circuit board with a Microchip switch (KSZ9897) going to a Ethernet-to-VDSL module (LX200V20).
The PHY ports between the two devices are connected using a transformerless connection ...
0
votes
2answers
123 views
How find the optimal frequency of a high frequency transformer
I have disassembled a "Chinese" power inverter, I found a High-Frequency Transformer, with no label on it.
I would like to make an inverter using this transformer to generate the High voltage to feed ...
2
votes
1answer
96 views
Change in duty cycle of a transistor (BJT)
simulate this circuit – Schematic created using CircuitLab
I have recently been working on a project in which my requirement is to transmit the data through a transistor, at a typical speed of ...
6
votes
1answer
132 views
High Frequency Characteristics of Solder-Filled Vias
If a via gets plugged with solder, does this destroy its ability to pass high frequency (RF noise) currents? Since there is no longer a surface along which the high frequency currents can travel due ...
1
vote
2answers
216 views
High pass filter for use in amplifier circuit
I've designed an amplifier for a small ac signal (amplitude of around 5mV, frequency 252kHz) with a BJT (2N2222.)
The BJT is set up in a common emitter amplifier configuration, with the biasing ...
4
votes
2answers
423 views
Question relative to pads for capacitors - high frequency
In the article
Compact sub nano second pulse generator using avalanche transistors, I read P. 874
Further, we used pads on a doublesided
0.062” FR-4 epoxy glass laminate pc-board for
...
4
votes
2answers
358 views
Calculating Wattage for Resistor in High Frequency Application?
I am making a MOSFET driving circuit.
Frequency : 400 kHz [50% duty cycle]
Gate voltage: 12 V
Total gate charge : 210 nC as per datasheet IRFP460
Rise time: 100 ns
[Q=I*t]
Current: 2.1 A
Gate ...
6
votes
2answers
437 views
How does one measure the Fourier components of a signal?
I attended a lecture on ground penetrating radar (GPR). I am used to reflection seismic where the incoming pressure amplitude is measured as a function of time.
In GPR, instead the Fourier components ...
0
votes
0answers
46 views
What kind of Modulation? Who transmits on 850 MHz (LTE-Uplink or GPRS?)?
Hey, I found an interesting Signal on 850MHz (in Germany). It is not symmetric and very strong (relative to many others due to bad antennas). On the right side the bandwith is permanently used, on the ...
0
votes
1answer
69 views
Can I bridge output IO's from an FPGA that is driving a clock source to drive longer tracks?
Scenario
I have a motherboard and a daughterboard that couple through two headers.
The motherboard has a 16x16 array of ultrasound speakers each with their own drivers, that works. I drive them ...
12
votes
4answers
1k views
Why isn't there a non-conducting core wire for high-frequency coil applications
Background
The commonly known skin effect formulas are derived and only apply to solid conductors. The commonly used "skin depth" only applies in these cases. It is for this reason that in some ...
0
votes
1answer
57 views
Can you make an electric gamma ray emmiter by adding up frequencies with freq. mixers up until you reach gamma ray herz quantities?
I just thought this up. Theoretically if you can add freq numbers you can get to large quantities like in a calculator, only this time mixing electric frequencies using amounts of circuitry right? Is ...
1
vote
1answer
102 views
Need a technique to rectify high voltage high frequency
I recently made a high frequency transformer which I will be using to drive a large spark gap tesla coil. I machined the bobbin at work from nylon and bought the 60x55x15 cores on Mouser to form a ...
1
vote
1answer
213 views
Switching high voltages with MOSFET at high frequencies
I need to rectify 220V 50Hz AC power to obtain 48V DC output voltage. Up to 40A current can be drawn from the DC side. 10% ripple is acceptable on the rectified voltage.
I am considering two ...
0
votes
0answers
180 views
Choosing an inductor for a bias T
I'm creating a Bias-T circuit for a certain application. When choosing my inductor to block my AC-signals I know for example the proper inductance to choose etc. However, what I am having trouble with ...
1
vote
1answer
59 views
Paralleling LVPECL outputs?
I have a pretty unusual application here, where I need to drive a fast differential signal fanning out into 8+ 100ohm transmission lines. The unusual part is this: the transmission lines must be ...
0
votes
2answers
68 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 ...
1
vote
1answer
138 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
102 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
538 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
133 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
votes
2answers
514 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
122 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
116 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 ...
