# Questions tagged [frequency]

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

1,115 questions
Filter by
Sorted by
Tagged with
55 views

### uC-adjustable harmonic oscillator circuit @100W

I'm looking for a circuit that performs a harmonic oscillation while its resonance frequency can be controlled with a microcontroller (preferably via an analog signal). The circuit has to drive a set ...
62 views

### Interpreting this bode plot

I ran a frequency analysis on a conductive textile I have designed and I am not sure what to make of this bode plot. My background is in textile design, not engineering. Does this make sense to anyone ...
88 views

### What RF frequency can I freely use without a government's permission legally?

So I want to create a transmitter that sends digital signals that have 30 kilometres of range but in my country. Radio transmission without authorisation is only allowed upto 50 metres. I researched ...
58 views

### How to see Signal frequency and Sampling frequency on the frequency spectrum

If I have a 100 Hz periodic analog signal and let us say it is band limited to 1kHz and I sample it at 3 kHz. If I want to see its frequency spectrum then how to differentiate between the signal ...
412 views

### Capacitor with specific self-resonant frequency?

I have a datasheet that calls for "a 15 pF capacitor with Self-Resonant Frequency in the 1800/1900 MHz range". It then recommends a capacitor (Murata GRM1555C1H150J) that (so far as I can tell) from ...
172 views

### Physical implementation of a band pass filter does not match simulations

I am building a pasive bandpass filter with the band pass between 134MHz and 139MHz. It is a third order eliptic filter, with theoretical attenuation of around 50 dB for the stop band and less than ...
94 views

### Will this High Frequency AC Signal Generator Circuit work?

I am going to make a variable DC to AC (10-100kHz). The circuit controlled by 2 PWM Signal from microcontroller to drive NMosfet connected to pull signal from two Ferrite core Transformer primary ...
44 views

### Trying to find value of two capacitors using resonant frequencies in three conditions, but wrong formula is derived

I was trying to find capacitance of two capacitors in the following way. Connect each capacitor individually to a same inductor and find resonant frequency in each case. Connect the same capacitors ...
31 views

### MOSFET channel length

Good day, If you look on google for ARF446/447 in the datasheet you won't find the channel length (in micrometers). I need it to calculate the unity gain cutoff frequency. Also in the case of IRFP360 ...
209 views

### IRF520 max frequency

I'm having trouble supplying 300mA to an led COB using an IRF520 MOSFET as PMW, controlled with arduino nano. What is the maximum Frequency, in which I can turn the led on and off in this setting? ...
85 views

### Video clocking: crystal or generator?

The video processor (VDP) has 6*Fsc (21,47727 MHz) clock inputs, pins XTAL1 and XTAL2, which is inversion of XTAL1. Present circuit is built using quartz oscillator of above mentioned frequency, and ...
70 views

### Phase, Frequency and Laplace transform

I have a doubt on the relationship between phase and frequency. We know that the definition of angular frequency is: ω(t) = d($phi$(t) / dt, where $phi$(t) is the istantaneous phase of our ...
67 views

### PLL (Phase Locked Loop)

I find a bit of confusion on the web about the use of the PLL. Sometimes I read that, given a certain input signal, it is used to generate a signal whose frequency is N times that od the input one, ...
89 views

### How to design a contactless mechanical shaker [closed]

I am trying to design a circuit to make an inductor oscillate with high-current (around 50A) at a low frequency. The inductor will act as a high-powered electromagnet. Most designs I've worked/messed ...
241 views

### 1/4 wave monopole PCB antenna design

I followed the below procedure to design a 700MHz 1/4 wave monopole PCB antenna. Is this correct? ...
178 views

### Admittance, Conductance, Susceptance definition

Admittance is the reciprocal of impedance. But: 1) Susceptance is the reciprocal of reactance, or the imaginary part of admittance ? 2) Conductance is the reciprocal of resistance, or the real part ...
42 views

### FCC EIRP test results different than other countries

We have an issue with regulatory testing where our lab reported EIRP varies significantly between separate labs who have tested for FCC and another country. The test methods are quite different. The ...
62 views

### Implications of dynamic frequency scaling in an embedded system

Dynamic frequency scaling is used to increase or decrease the speed of a processor to conserve power, heat, etc. I've seen my own processor fluctuate between 3GHz and 3.5GHz. What are the ...
148 views

### Frequency comparator circuit in LTspice not outputting expected state

I'm trying to simulate the circuit in the method shown here in LTspice as: I use the same parts 74HCT74 and 74HCT00. But the circuit does not function. Here I set F2>F1 and the outputs at R1 and R2 ...
48 views

### How to choose an antenna for an FM transmitter? [duplicate]

Ok guys I can't understand something. Say that I have this circuit: Assuming that I apply at the antenna 5V, how can I calculate how much power I will trasmit? I found on internet that the current ...
52 views

### demagnetising a magnet with a high frequency transformer

This is a theoretical question. Some elements described in the problem may be impossible/impractical, but I am just trying to understand the principles. It is kind of a physics question, but also ...
68 views

### How to transmit a signal to a point [closed]

I have a signal generator (Digital Dual Channel Funktion Signal Generator) and want to generate two signals (530 and 550 Khz signal) and want to transmit these generated signals to the points on a ...
212 views

### How do we define resonant frequency for a circuit, that has arbitrary combination of resistors,capacitors and inductors?

How do we define resonant frequency that has arbitrary combination of resistors,capacitors and inductors? For instance inductors and capacitors may neither be in series or parallel, but may ...
45 views

### Convering bandwidth (frequency) to bit rate without knowledge of the modulation?

How would i convert a bandwidth of say 30kHz to bps if I only know the number of bits per sample (4)? (and I was using a two chanel system). I am assuming it is simply 30KHz * 2 * 4 but this may be ...
164 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 ...
60 views

### Relating frequency domain to Bandwidth

I was just wondering about the frequency domain with regards to bandwidth. I am not sure how to relate the bandwidth of a signal to its frequency. For example, I have a Fourier transformed equation of ...
194 views

### FSK generation with Timer 555

On the Internet I found FSK generator connection diagram. And I'm trying to connect up it in Qucs. I' sure, 555 timer is working properly. But at the output of the whole schema I get unclear result. ...
67 views

### Variable Frequency-Response analysis (amplifier)

I'm trying to understand what the book "Basic Engineering Circuit Analysis" by Irwin is saying at the chapter of variable frequency... It's trying to amplify a signal from 50Hz to 20000Hz. Where it ...
43 views

### Are magnetically tunable surface acoustic wave devices commercially produced?

I have been reading up on studies of magnetically tunable surface acoustic wave devices, in general they note the relative velocity change or in some cases a frequency shift if it is part of an ...
299 views

### Phasors and Fourier Transform

I have always been told that for a sinusoidal variable (for instance a voltage signal), the fourier transform coincides with the phasor definition, and this is the reason why the analysis of ...
43 views

### Is there a difference between rise and fall time and modulation frequency

I was wondering if there was a difference between modulation frequency and rise and fall times of a laser diode or LED? If a laser had a modulation frequency of 100MHz would that be the same as a rise ...
40 views

### Is there any physical limitation to cell carries sharing the same frequency?

Currently in the U.S. certain companies are granted leases on certain frequencies for cell phone communication. I was discussing with a friend how this allows a company with a lower frequency to get a ...
99 views

### Why can the energy of local computing be written as $f^2$,not $v^2$

I saw this formula in this book: Wireless Information and Power Transfer: Theory and Practice And in the formula 14.8, it said: $f_{i,n}$ is the CPU frequency for the nth CPU cycle required for ...
29 views

### LTspice Monte Carlo analysis vs. .meas command

I designed some analog second-order all-pass filter in LTspice and provided Monte Carlo analysis as well. I want to evaluate the obtained AC results with .meas command, particularly: Magnitude ...
58 views

### Bode diagram calculating for random frequency

The max Gain of an opamp is 100dB (=100000). I have a cutting frequency at 10 Hz and then the slope of my bode diagram decrease by -20dB/dec . I have unity gain at 1MHz. For 100 Hz its increasing by ...
35 views

### FIR Filter Transition Coefficient

Design a length L=40 linear-phase FIR filter using frequency sampling design with an optimum approach. Use the transiton coefficient table given in Proakis and Manolakis. My M is 39, how can I use ...
28 views

### Bessel function normalization graph

This graph is drawn bessel function table but ı stick around reading table.Does table gives directly frequency spectrum amplitude values or only jn(ß) values?
172 views

### Does data rate increase with channel frequency?

It is commonly said that a higher channel frequency implies a higher data rate. For example, in https://www.howtogeek.com/222249/whats-the-difference-between-2.4-ghz-and-5-ghz-wi-fi-and-which-should-...
79 views

### Measuring accuracy and counting frequency?

The machines at my workshop have meter counters with hall effect sensor switches, which convert shaft rotation to electronic pulses. The switching signal is send to their PLCs' high speed counter ...
74 views

### How to improve flash time on lights controlled by solid-state relay via Arduino?

My goal is to flash lights around the house on and off to the beat of a song. When doing this with a mini LED and an arduino, it works perfectly with a "flash_time" of ~.1 seconds. This means ...
40 views

### Measured doppler shift error biggest on direct flight on target

Following scenario: There is a radar on a plane which emits a CW Signal and outputs the measured doppler shifts from the reflection of a static target. I can see from the data, that the error of the ...
120 views

### Reading a high rate (400 kHz) analog input with an ESP32 (or Arduino)

Tried Googling this but I'm not really sure what vocabulary to use. I have a series of light sensors that will be detecting changes at the speed of 400 kHz (or 2.5 µs). I would like to use an ESP32 ...
124 views

### How to reduce full sine wave LUT to a singe sine quadrant?

I have implemented a full sine wave LUT, but would prefer to reduce it to a quarter. ...
133 views

### How to change frequency range of this circuit

I need to design a frequency to voltage converter and I found this circuit on internet: I removed the resistor R6 and the capacitor C5 because what I need is the PWM output it gives on the 555 timer. ...
36 views

### Can MCPCBs be used for audio frequency and/or MCU clock frequency applications?

For purely aesthetic reasons1, not for heat dissipation, I am contemplating using MCPCBs for these two applications: Audio frequency circuits, such as a Baby 8 sequencer, Atari Punk console, ...
70 views

### SIMPLE digital control over 555 timer frequency and PWM?

I'm looking to create a sound generator with only simple ICs and components. I believe the 555 timer IC is a good candidate to be at the core of it, but I cannot for the life of me find out how best ...
119 views

### Crockcroft-Walton Voltage Multiplier Large Voltage Loss

I have a CW voltage multiplier that uses 30kV, 1nF capacitors and doubled 20kV, 5mA, 100ns diodes (for a total of 40kV). My ac source is a sine wave (viewed on the primary side of the transformer ...
35 views

### producing a continuous sound using a timer

I'm looking to produce a pure sound on one frequency to be played via a timer to come on at intervals over a six week period. this is for an undergrad dissertation. would an arduino work and could it ...
187 views

### How can I change a DC current to a 1.7/2.4 MHz AC current for piezoelectric device

I would like to start by saying my experience in electronics is very limited and I will include pictures of everything. I am, however, trying to assemble a device which puts a current through a ...
85 views

### Pulse width for mark pulse

What is the pulse width for the mark pulse in an equal mark to space ratio pulse train operating at a repetition frequency of 5 MHz? The answer is suppose to be 100 ns .But I didn't understand how to ...