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# Questions tagged [frequency]

How many times something happens per second, measured in Hz (hertz).

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### What is the correct formula for the 3db frequency of an RC or LC Circuit?

Before we jump to another post where the formula is I am reading through the text book Microelectronic Circuits 8th edition by SEDRA/SMITH. In the text, they show this table. Here it shows the time ...
0 votes
2 answers
33 views

### Simple square wave frequency multiplier/divider

I have a square wave 0-12 V input signal that varies from 30-150 Hz, which I wish to multiply to an output square wave 0-12 V signal of 60-300 Hz. In this case, the multiplier is 2, however I ideally ...
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2 answers
151 views

### Does the oscillation frequency of my step-up (boost converter DC-DC) depend on the characteristics of my motor?

I have to step up a 4V supply (the generator is a button battery) to a 12V voltage to supply my motor. How do I size the components of my step-up converter? To compute for example the inductance and ...
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77 views

### Need Help Increasing PWM Frequency from 800 Hz to 8000+ Hz for DC Motor Speed Control

I'm currently developing a speed control system for a powerful 12V DC motor that pulls a heavy load. To enhance system efficiency, I need to raise the PWM frequency from the 800 Hz (PLC upper limit) ...
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1 answer
143 views

### How to calculate frequency of an AC source with variable frequency using Arduino

I have an AC current source. Its properties are Maximum Vrms=15v Maximum Frequency 125 Hz Minimum Frequency 5 Hz The current source is pickup coil of a motorcycle... Vrms range is approximately 0.7v-...
-1 votes
0 answers
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### Gain depending to Frequency [closed]

This script sets up a server that listens for incoming connections. It reads audio data from the client in chunks of 1024 bytes, processes it using FFT (Fast Fourier Transform) with frequency-...
1 vote
1 answer
152 views

### 1200W, voltage and cycle converter 220 to110

I have bought a Joule sous vide immersion circulator from USA. I want to use the device in India. I need to convert AC, 240V 50Hz to 110V 60Hz. After reading the literature on the company's website ...
2 votes
1 answer
93 views

### Why does a MOSFET fail on fast signals, even if they're much longer than the turn on + turn off times?

When running at a fast signal, why does the MOSFET below not turn off, even when gate voltage is well below threshold (even negative)? Although the signal is fast (7 MHz, 140 ns period) it is < 1/...
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1 answer
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### Oscilloscope Total Record Samples Vs Signal Frequency

I have the oscilloscope R&S® RTC1000 at 300MHz / 2GS/s / 500Mpts (Mega Points) with 12 horizontal divisions on the screen. 1st Example: If I have a signal 1Hz the total samples that the ...
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41 views

### How can I determine how much power is in a frequency range via FFT in LTspice?

When using LTspice, I can see the FFT of a voltage. How can I see how much power is in a particular frequency band, and what portion of the total power it is? The FFT in LTspice is in dB, but it's ...
2 votes
1 answer
1k views

### FSK demodulation with LM565

On the Internet I found FSK demodulation connection diagram with LM565 . And I'm trying to connect up it in Qucs. At the output of the whole schema I get unclear result. In my previous topic we were ...
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1 answer
166 views

### If I look at a signal in its frequency domain, are there some guidelines by which I can tell how that signal looks in the time domain?

I was studying the Laplace transform and the Fourier transform, and I can't figure out if there is some intuitive way of finding out how a signal looks in the time domain if we know its frequency ...
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### What does the standard deviation of TIE measurement tell me about my clock signal jitter?

When we take a Time Interval Error (TIE) measurement of a clock signal, we are presented with two measurement outputs, the mean error and the standard deviation. When I measured the TIE of a 32....
1 vote
2 answers
126 views

### How can I find the resonating frequency of a piezo crystal?

The crystal looks like in the given image I want to find the resonating frequency, whether is it variable or fixed. I find its manufacturer has not given much detail about it. Does a piezo resonate ...
1 vote
2 answers
169 views

### In a ZVS circuit, why does frequency increase when an arc forms?

In a GreatScott video, when he made an arc using a ZVS circuit, the frequency jumped from 40 kHz to around 80 kHz when the arc formed. I read that this is because the inductance is reduced because of ...
2 votes
3 answers
2k views

### Opto-coupler base connection speed influence

I am using a 4N25 opto-coupler for 5kHz to 10kHz application. In some datasheets the turn on and turn off times are mentioned to be 3us. I am wondering if this opto-coupler is suitable for my circuit'...
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### Change analogWrite() frequency using the arduino framework for SAMD51

I am using Adafruit Feather M4 Express board which has Atmel SAMD51 controller on it. I am using platformio as IDE, which lets me use this controller using the Arduino framework. I want to change the ...
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1 answer
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### Oscilloscope Low Sampling at uHz Sinus Signal

I tried to measure a sinus signal at 1000 µHz with my R&S RTC1000 oscilloscope (bandwith 300 MHz). The function generator that I used was the EDU33212A. I set the T/div=100s and the oscilloscope ...
1 vote
0 answers
65 views

### How to generate a 50-100 Hz 12 Vac sine wave for audio tone from 5 VDC (PB0 pin) atmega164p microcontroller [closed]

I have programmed to ATmega 164P to make PBO high when PC1 is low. In programming, I'm adding other peripherals as well. But I am facing one issue regarding generating a tone. I have drawn low pass ...
1 vote
1 answer
175 views

### High frequency relay options for 5V 20A DC

While researching for a while upon relays, I had a hard time finding out how to choose a relay that can switch high DC currents at frequencies up to 20MHZ. I found those solid state relays, but most ...
-1 votes
2 answers
84 views

### How to modify frequency of an analog signal [closed]

I want to create my own pcb. First step is to design my circuit. I thought about a voice modifier. So, in the breadboard I should put: a microphone (an electrostatic electret microphone) followed by ...
1 vote
4 answers
2k views

### Why are capacitors high-pass / low pass frequency elements?

I'm trying to study for my intro circuits class final and always found the idea of impedance and filters confusing. Take these two circuits: The first confusion is where are we even measuring the ...
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1 answer
103 views

### When increasing the frequency of an induction motor can't I just add a capacitor to maintain torque instead of increasing the voltage?

When increasing the speed of an induction motor if one wants to maintain the same torque, the voltage has to be increased at the same proportion as the frequency of the AC supply. This is because the ...
8 votes
5 answers
2k views

### Changing output impedance of a logic gate to 50 ohm

I making a simple circuit to take 10 MHz output from a GPS module and calibrate a frequency counter with this 10 MHz signal. I have already found a circuit designed by radio amateur ZL2PD. Circuit ...
1 vote
1 answer
175 views

### mechanical excitation of tuning fork and electrical readout

For my experiment, I am trying to mechanically excite a quartz crystal tuning fork and measure the voltage across the tuning fork. When the TF is driven at its resonance frequency, there should be ...
2 votes
4 answers
3k views

### How to halve a frequency with analog circuitry while preserving signal integrity?

The question is simple, the answer I'm not sure... How could I pick up an analog audio signal, divide it's frequency by 2 (one octave lower) and send it back on it's way? I could do this by sampling ...
1 vote
2 answers
134 views

### Having trouble with a 555 Astable timer outputting into NPN transistor switch that controls 741 Op-Amp

I have been building a circuit that takes the output of a 555 IC and outputs it into an NPN transistor that acts as a switch to toggle a 741 Op-Amp connected to an 8 ohm, 0.5 watt speaker. I'm new to ...
1 vote
1 answer
208 views

### Why do GPU's often have a different core frequency and shader frequency?

Typically GPU's have a faster core frequency and shader frequency. Typically the shader frequency is double or more than double that of the core frequency (e.g. 607 MHz and 1215MHz for GeForce GTX 590)...
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2 answers
158 views

### More voltage for radio carrier frequency, is that all?

I soldered one radio circuit for a wave transmission with ~107 MHz frequency and I got good results. I simulated this circuit in LTSpice, too. What I have seen was that the wave got AM modulated and ...
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2 answers
117 views

### Why is the gain of the amplifier not considered in the frequency calculations? (Sedra and Smith 6th edition, Example 1.5)

In example 1.5 in Sedra & Smith 6th edition, the author's answer for item b) is 1 Mrad/s. To get this answer, the author considers the amplifier as a passive LP network and uses the time constant ...
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2 answers
162 views

### Why is the Gb/s usually matched with the GHz for SDI?

My knowledge in electronics and RF(because high speed data) is very surface level but attempting my best. I'm attempting to do an application which utilizes 3G SDI, but am not understanding why there ...
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3 answers
527 views

### Antenna tuning for a multi-band antenna

I have a PCB antenna that supports multiple band antenna. https://www.johansontechnology.com/datasheets/0830AT54A2200/0830AT54A2200.pdf We also have a tune circuit before the antenna as recommended by ...
1 vote
2 answers
136 views

### How to use this crystal oscillator? [closed]

I recently bought a 315Mhz crystal oscillator off of Amazon but I can’t figure out how to use it nor can I find any information online about it. The only thing I can find on them is that picture. I ...
26 votes
5 answers
2k views

### What are 12.000393 MHz crystals used for?

I found them on www.digikey.com, and they're apparently made by different manufacturers, so there must be some use for them. What are they used for? edit and why? The 2400 baud modem doesn't offer an ...
1 vote
2 answers
317 views

### What are the gain and phase margins from this Bode plot?

I thought I had a decent grip on how Bode plots work yet for this model that I am working on, I need to implement a lead or a lag compensator. A lead compensator, which I was thinking about ...
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### Difference between radio transmitter roll-off and bandwidth-time (BT) product

For any radio transmitter, the output signal will likely have a shape filter to manage bandwidth. However I am struggling to understand the relationship between a roll-off (e.g. 0.35) and a bandwidth-...
3 votes
1 answer
271 views

### Generator frequency control

We are trying to run an AC generator on an RV for a customer. On an RV as you drive the engine RPM goes up and down. As I understand it, that would change the outlut AC frequency. Is there an ...
-1 votes
1 answer
67 views

### What is minimal frequency to detect such signal? [closed]

I develop simple signal generator, to debug other devices. It sends high logic signal which has length approximately time length 64 microseconds. If i connect some device which has processor frequency,...
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### WCCA analysis - Induction selection - Mismatch with recommendation at low current values

I'm performing the WCCA analysis of a 3.3V buck regulator(AP64200Q). Datasheet: https://www.diodes.com/assets/Datasheets/AP64200Q.pdf In the current circuit:Vin=24V,Vout=3.3V,Max.current=300mA so ...
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3 answers
100 views

### Amplitude modulation problems

I am trying to do amplitude modulation using a diode, but my circuit will not work. This is the circuit I am using: simulate this circuit – Schematic created using CircuitLab I don't know why ...
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1 answer
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### Specific frequency filter

I want to use an insolation monitoring system that outputs different frequencies for every state. Exactly 0, 10, 20, 30, 40, 50 Hz but I want to use the 10 and 50Hz only. Is it possible to build a ...
1 vote
2 answers
82 views

### Using an LT1357CN8 to amplify the signal of a 1.5 MHz frequency generator

I am working on a frequency generator to control piezoelectric transducers. I use an Arduino Uno R4 Minima to send data to an AD9833 which creates my desired sine wave up to the required 1.5 MHz. ...
1 vote
2 answers
3k views

### Sine Function on Simulink

I'm trying to add the following function on my Simulink model. where C, B, and N are already variables in my file. Is the correct way to multiply omega by the gains 3N and N/2 an input that into the ...
1 vote
1 answer
221 views

### Converting an FM square wave into an FM waveform that is sinusoidal

How could I convert a frequency modulated square wave, like from the timer 555 output, into a frequency modulated sine wave? P.S. I added here the image of the circuit schematic for a more complete ...
1 vote
1 answer
337 views

### How does a PLL PFD produce a high frequency?

I am going to work with a PLL and a VCO. I have read and understood the basic procedure in which the charge pump works. I understood that say, when the reference signal (or the divided signal) is up ...
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### Animal repellent circuit for cows and goats

I want to create an animal repellent circuit for my school project but I'm having some problems designing the circuit. The circuit does not produce any sound frequency. NB: We are not allowed to use ...
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0 answers
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### What is minimum gain crossover frequency in bode analysis?

I know gain crossover frequency at which magnitude of open loop transfer function is 0. But what is the case here for minimum Wgc?
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2 answers
661 views

### How to calculate PWM duty cycle to compensate for different piezo sounder response at different frequencies?

How to calculate PWM duty cycle to compensate for different piezo sounder response at different frequencies? I have a piezo sounder, and the datasheet informs me that I will get the following ...
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1 answer
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### SPWM - Frequency calculation

Below is the SPWM I produced with 50 Hz sine wave and 5 kHz carrier signal. I will use the SPWM signal to drive the MOSFETs in my inverter. As it is known, duty and period are constantly changing in ...
1 vote
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### ledcWriteTone leaking to other pin?

I've recently written a program that involves two blinking LEDs. I have these LEDs wired straight from the pins into GND. One is set to blink on and off on one second intervals, and the other is fed a ...