This tag marks questions related high frequency (radio) circuits.

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14 views

Where to salvage inductors?

I need a toroidal inductor for my ZVS flyback driver. The value should be between 47uH to 200uH. It should be able to handle 6A. Where can I salvage them from?
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0answers
12 views

NE555 Flyback Driver MOSFET failiure

simulate this circuit – Schematic created using CircuitLab I made this simple NE555 Flyback driver. I used a 9V Battery to power the NE555 and a 24V 6A power supply to power the flyback. ...
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2answers
64 views

How to amplify a 2MHz signal?

I am working on ultrasound sensors. At the receiving end I have a 2MHz signal of 80mV p-p. I need to amplify it at least by 10 times. Please suggest an appropriate method. Additionally, I need to ...
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0answers
20 views

Minimum Distance for Corner Reflector

In RF-Measurements Trihedral corner refelctors are often used as calibration targets because of their constant and analytically defined radar cross section. The RCS of a trihedral corner reflector ...
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2answers
94 views

Why does more bandwidth mean higher bit rate in digital transmission?

I understand that similar questions like this one have been asked before on this site, listed below. However, I am confused about the answers. If I explain what I think I understand, can somebody ...
2
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2answers
94 views

Minimal distortion in transmission line

In a transmission line, the condition for minimal distortion (caused by the line) are when (R/L = G/C) in the line, right? However, I don't see any reference to that in any application notes or ...
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1answer
64 views

IC555 flyback driver troubleshooting

I made a flyback driver which just uses an astable 555 circuit to drive the flyback. The 4 and the 8 pins were connected to the positive rail. 7 pin was connected to the positive rail via a 1K ...
4
votes
1answer
89 views

How can I track where this 471kHz noise is coming from?

I'm new to EE in general and I just received my first oscilloscope (Rigol DS1102E). Anyway, I'm building an audio circuit using an Arduino Micro and the infamous ...
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1answer
122 views

How to make prototype circuits that include microcontrollers, and avoid breadboard annoyances at high frequencies?

From my searches of the web ( as well as this question ), I have found that breadboards - like the one on picture - aren't a good idea when your application involves high frequencies. I am going to ...
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1answer
157 views

How to design a 1-500MHz sine wave level detector to -90dBm?

I want to build a sine wave level detector that works for a single 1-500MHz sine wave in the range of -40dBm to -90dBm. This is a hobby project - so cost is not a big obstacle :-), but I want to stay ...
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2answers
2k views

Can anyone explain this high-frequency “alien voodoo black magic”?

I was casually watching Mike tear down a spectrum analyser (13:30 is the relevant part, 16:50 is the awesome part), and he came across what he aptly described as "weird messed up alien voodoo black ...
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2answers
216 views

How does an increase in operating frequency result in decrease in the size of an inverter circuit?

I was reading about inverters in a textbook where the author says that The size and cost of the circuit can be reduced to some extent if the operating frequency is increased but then inverter ...
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2answers
94 views

Describe qualitatively the amount of current passing through resistor if the source oscillated at low frequency?

I am stuck on lab question 3. I do not know how to determine the current crossing the resistor for oscillating current at varying frequencies. Help is greatly appreciated
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1answer
69 views

Looking for High Speed Parallel DAC IC without data latch

I have designed a FPGA based DDS that creates digital signals between 0-70MHz. Now I want to convert my digital data into analog. As the base frequency is 200MHz, I need a high performance parallel ...
2
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0answers
84 views

High voltage, high frequency, pulser

For a rather unusual application, I need to generate high voltage (>500V) pulses with a very short rise time (10-100ps). Is there something that can do this off-the-shelf? Assume money is no object. ...
0
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1answer
127 views

Confusion regarding considering a transmission line as lumped or distributed

I am just elaborating my question. I have came across different formula's to say whether a Transmission line is lumped or distributed. in one of the books i read " Effective length of a electrical ...
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2answers
123 views

USB Full Speed driver with MCU in DIP package

I desire to apply a USB driver with a MCU that has a DIP package. The device should communicate in Full Speed (12 Mbps). To your experience, is that possible? Taking into consideration the physical ...
3
votes
1answer
87 views

What concerns are there with running high frequency traces?

I am working on a project where i will be laying out some traces that will be handling Gigabit Ethernet traffic. I know that putting these traces on the outside layers (Top or Bottom) is a bad idea, ...
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1answer
217 views

Running JTAG chain over busy backplane

We are busy designing a large system with around four PCBs slotting into a backplane. Each PCB could contain a DSP as well as a large FPGA. We would like to run 2 JTAG chains through the system, one ...
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1answer
216 views

What kind of waves can penetrate walls/floors and cause tingling, headache, nausea, etc? [closed]

What types of waves would be able to penetrate walls and floors and at high frequency or intensity would cause symptoms like tingling or burning skin, headache, nausea, and heart palpitations? I know ...
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1answer
522 views

What, if anything, makes shielded loop antennas so great at rejecting local noise?

There is a folk wisdom, among amateur radio operators, that if you have a lot of noise on HF, such as in an urban location, then using a shielded magnetic loop antenna for receiving is really great ...
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2answers
178 views

How does this circuit multiplex an antenna between a transmitter and receiver?

I've built a Softrock RXTX kit (full schematic: pdf gif, see lower-left corner). It has one connector for one antenna used for both receive and transmit, but I don't fully understand (likely due to my ...
3
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2answers
222 views

Ground vias on high speed PCBs

I know that if I use vias on high speed traces that I need to reduce the inductance effect of the via. So I will put ground vias next to these vias to help returning current. I have seen a picture ...
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1answer
193 views

Why cable TV frequency range ends at 1 GHz?

Currently frequencies 50-1000 MHz are allocated for TV and data transfers. I understand why there are limitations for aerial or satellite transmissions, but why are they retained for cable ...
2
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1answer
113 views

Filtering High Frequency Channel Noise

I have a signal that should have this theoretical shape: The signal I am receiving experimentally has the following shape: And here is a plot that better shows the shape of the waveform (I have ...
4
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3answers
251 views

Reduce and clip voltage of a 5Mhz ultrasonic signal from +-50V to 0-3.3 V

I know there are a lot of posts similar to this one but some differences make it worth posting it. I’m working on a project where I have a 5MHz AC signal with the largest amplitude of +-50V. It’s an ...
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4answers
138 views

sub-kilohertz channel spacing with PLL

So I'm trying to use one of Analog's evaluation board PLL circuits (ADF4350, here). I need to generate frequencies around 1 GHz, ideally in a +/- 250 MHz range, but in steps of < 1 KHz. Using the ...
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1answer
129 views

Poor RF communications : looking for advices [closed]

I am in charge of a temperature monitoring and controlling project in a new building with 7 floors and 14 rooms by floor. I installed last week thermostats devices in each rooms permitting to send ...
3
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1answer
97 views

Name for circuit with multiple paths with aim of reducing inductance

Trying to find the best way of describing a circuit that uses multiple separate physical paths to reduce effect of inductance on by HF signals. Is there a term for such?
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1answer
417 views

Why high voltage from TV flyback shocks you without the need to complete a circuit?

Assuming the TV is plugged into an isolation transformer (although I think there is already a small transformer onboard), then ground is not part of the secondary side. Yet, high voltage from flyback ...
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2answers
121 views

10A power suply, high frequency

An EL wire consume ~10mA/m, and need a 1800Hz, close to main voltage, sinusoid supply. (The noise is not a matter as the EL wire itself will cut off the frequency >2kHz). for an installation I would ...
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3answers
545 views

Measuring high frequency current with Adrunio

Is there a way to measure the current of a high frequency signal (100Khz) with an Ardunio? I am thinking that some form of analog circuit could be made whose input takes AC current and whose output is ...
2
votes
1answer
263 views

How can I superimpose Pulse signal

I designed this circuit, put V1 as sinusoidal source and output was good at oscilloscope.However when I changed V1 to pulse signal there was no output on oscilloscope. Thanks to tell me if pulse ...
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3answers
549 views

How is a transformer working at 10's of MHz designed?

In this answer a switching power supply using a transformer operating at 10's of MHz range to reduce size is mentioned. How would such transformer be designed? Would it still have a plain old design ...
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1answer
276 views

Connect SMA to a regular pin/wire

I have an RF signal (5ns pulses every 200ns) coming out from a SMA connector on FPGA board (Spartan 3E Starter Kit). I want to send this signal back to the FPGA using one of the on-board pins. So, I ...
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3answers
165 views

Ultra high bandwidth serial data stream

I have a ultra high bandwidth data stream (USB 2.0 Highspeed), on which I need to add an header for synchronization. This needs to be done, since the datastream needs to be transmitted wireless on a ...
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2answers
362 views

How does this circuit attenuate high frequencies?

I understand that this circuit could be used as a treble control circuit with high frequency gain occuring when R3 is set so a=b (we'll call this k=0), and high frequency attenuation occuring when R3 ...
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2answers
320 views

How to test RF (1GHz) PCBs?

I have a number of RF PCBs. I would like to test these PCBs, so can someone guide me as to how to test these PCBs. The list of the PCBs that I want to test is mentioned below. 4th order Butterworth ...
2
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1answer
294 views

Signal reflections at the driver?

This question is related to How do I use directional couplers on a differential signal? I understand that if I have an impedance mismatch at the end of a signal cable, E.G. from a terminator which ...
2
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2answers
389 views

How do I use directional couplers on a differential signal?

I understand how a directional coupler can be used to measure signals travelling in one direction on a wire. What I don't understand is exactly how this would work on a differential signal, E.G. LVDS ...
3
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1answer
283 views

What makes an active probe so expensive?

This question probably has a similar answer to Why are digital oscilloscopes still so expensive?. But why are active oscilloscope probes so expensive? I mean, they're hundreds, if not thousands of ...
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4answers
3k views

Is this a good design & layout of an active differential 'scope probe?

This question is an extension of Homebrew differential 'scope probe. I thought I should make this a new question though. I need to measure a 100Mb/s LVDS signal to check its integrity. I will try to ...
10
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6answers
3k views

Crazy homebrew 500 MHz 1 Gs/s oscilloscope possible?

I was reading USB scope probe - request for comments and ideas, and it got me thinking. What I'd really like is a very high performance oscilloscope, one which would cost $10000 or so. Surely many ...
4
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2answers
291 views

Does a 250MHz FIFO chip exist?

If I have 8-bit parallel data being clocked out of a chip at 250MHz, is there some way I can buffer it? I only need to store about 1kB. Preferably this would be a FIFO. Does such a fast FIFO exist at ...
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1answer
1k views

Homebrew differential 'scope probe

I may be able to get my hands on an old 600MHz LeCroy oscilloscope. However, it doesn't have any probes. Is it feasible to make an active differential probe for it using a high-speed op-amp, like the ...
5
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4answers
867 views

How important is it to put decoupling caps on the same side of the PCB?

How important is it to have decoupling capacitors on the same side of the PCB as the IC? I am desperately short of space in a design, and it would really help to put the caps on the bottom side. I ...
2
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2answers
960 views

H-bridge ic for high voltage and/or current

I tend to design my circuits around H-bridges, but the problem with making them out of standard mosfets is that I always have to compare the rise times, fall times, threshold voltage, etc of my ...
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1answer
249 views

MOSFET in high frequency applications

I've heard that MOSFETs for high frequency circuits are generally configured as common gate. Can anyone explain why? Could this be related with the internal MOS capacity?
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4answers
1k views

Clock generation using FPGA

I am trying to use Spartan 3E kit to generate 50 MHz clock. The kit comes along with a 50 MHz crystal which I am trying to use. So, I wrote a simple code to output the clock from the FPGA to the SMA ...
0
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1answer
549 views

How to output signal though SMA connector in Spartan 3E Starter Kit

I want to output a signal through the SMA connector available on the Spartan 3E starter kit board. Can someone guide me as to how to do it?