Questions tagged [frequency]

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

107 questions with no upvoted or accepted answers
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What determines the frequency of network cable

You have Cat6, 23 AWG, rated for 250Mhz frequency. You then have Cat6a, 23 AWG, rated for 500Mhz. Both are unshielded. How is Cat6a able to transmit data at a higher frequency then its counter part? ...
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1answer
123 views

Self-resonance frequency of chip inductors

I am studying chip inductors and here's one of the frequency response: There are more than one resonance frequencies exist in a single inductor. When we say inductor resonance frequency, it usually ...
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1answer
97 views

frequency response multistage

hello every one i need ask about frequency response i have an old question of our professor exam in few year, and i try to solve this question many time but i can't so please if any one have idea ...
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776 views

Bandwidth and Carrier frequency

What is exactly the difference between the Bandwidth and the carrier frequency ? And if we have two channels with the same bandwidth but with different carrier frequency will we have different speeds ?...
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748 views

How is it possible that lower CAS latency and lower timings on RAM memory to result in lower performance?

I have watched many benchmarks on RAM memories and I was shocked to find out that sometimes lowering the memory timings can result in lower performance in BOTH synthetic benchmarks general use of ...
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1answer
218 views

How do I calculate limit frequency of the attenuator circuit?

Calculate the limit frequency \$fg\$ of the attenuation \$v_u =\frac{ u_a} { u_e}\$ at the current source I (for the value given in example), so that for \$f>> fg\$ exist ideal behavior. Note: ...
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111 views

High Frequency Pulse Rate Generator - Science Fair

( For our High School Science Fair) I am trying to find a pulse rate generator capable of producing 2.5Hz - 20,000 Hz utilize with over 10,000 LEDs all at once with several milliseconds in between ...
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1answer
42 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 ...
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1answer
61 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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42 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 ...
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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 ...
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111 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 ...
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1answer
101 views

Are my calculations wrong?

So I'm trying to make relatively a large square coil antenna that will operate at 125kHz frequency. The width and height of antenna are 300mm (30cm) and wire diameter is AWG24 (0.51mm) and I'd like ...
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57 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 ...
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37 views

System requirement in frequency domain

Hi Can any one help understanding and interpreting figure 6a and 6b (page 6) in the paper attached down bellow : I need to identify first the transfer function of each plot and then interpret system ...
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1answer
53 views

Datasheet Notation for Filter Parameters

I've been reading through the LTC1264-High Speed Quad Universal Filter Building Block datasheet but I'm having some trouble deciphering the meaning of some of the variables used in the equations for ...
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95 views

Rubidium standard mystery output?

I've been playing with a frequency counter (Racal 2202R) that has a built-in rubidium standard. It has two outputs, "Rb OUT 1" and "Rb OUT 2". I could not find any documentation at all, but the ...
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125 views

How can I find the frequency of oscillation of this sawtooth oscillator circuit?

Simple question: how to find the frequency of oscillation of this circuit? simulate this circuit – Schematic created using CircuitLab My attempt at answering the question is the following: ...
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60 views

Variable frequency of an astable

I have to make the frequency variable of an square waveform generator built with the help of an astable. I modified a circuit a found on the internet and everything seems good with only one exception: ...
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1answer
41 views

True near field distance for a short monopole antenna

Antenna properties: Height x Diameter = 3.3 inches x 1.4 inches Test Frequency: 900 MHz (Wavelength = 33 cm or 13 inches) I see some conflicting formulas to calculate the near field distance for ...
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2answers
80 views

Period Measurement

I am reading a book about the measurement in communications. There are a lot of information about how to measure frequency and period of signals. OK, i have understood that we should measure the ...
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190 views

How to change frequency on ICL8038

I am making a frequencygenerator, that will have sine, triangular and square output (choosen with a rotary switch) but first, I'm having a problem with setting the right frequency with components. I'...
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1answer
171 views

First-order analog active bandpass filter with variable center frequency

I've thought about designing an active first-order bandpass filter with variable center frequency and fixed bandwidth, using OpAmps, as a project for an Applied Electronics class. My first try was to ...
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72 views

AC voltage through a capacitor

I've built a band pass filter to detect speed using a radar motion detector (IPM-165 http://nic.ath.cx/PDF/sensors/radar/CDM324-doppler/InnoSenT/InnoSenT_application_note_III_11_06.pdf). Using PSpice ...
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130 views

Generated current in a \$3\times450\$ VAC \$60\$ Hz \$1150\$ kVA generator

Let's say I've a \$3\times450\$ VAC \$60\$ Hz \$1150\$ kVA generator. How much current will there be generated when it runs at maximum capacity? MY WORK: The total Active power over a three-fase ...
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60 views

Change in frequency in a grid that has lost generation?

I have an example about droop and it asks to calculate final frequency in a grid after one generator power generation is lost. The answer is given as 59.889 Hz; however, I am calculating as 59.99 Hz. ...
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2answers
195 views

Minimizing frequency drift in LM331

Below is the schematics of a circuit so far I finalized and soldered on a perfboard: (please left-click to enlarge) Basically the circuit converts 0...10V input voltage to 10mV pk-pk square-wave. ...
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576 views

How to Reduce Current in Solenoid Coil

First time poster and electrical newbie here. First off I just want to thank everyone for helping create such a great and helpful forum! I've been lurking for years and have learned a lot here! I ...
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236 views

The relation between the current and frequency in ohmic resistance

In the Figure above, I was asked to determine which diagram refers to the relation between current frequency and the intensity of the current in an ohmic resistance. I am confused between (2) and (3). ...
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639 views

How to calculate total current drawn by a circuit

I have been trying a make simple alarm using LM324 and a buzzer. The circuit is pretty simple. I need to power it from my 9V/1000mAH battery. But here is the part am stuck. I don't know how to ...
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143 views

Can't get PIC16F1764 to run at 32 MHz INTOSC

I have a problem with a PIC microcontroller. I can't get it to run at 32 MHz. Via page 78 of it's datasheet (document number DS40001775B). The steps for selecting 32 MHz FOSC operation are clearly ...
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448 views

Relation between frequency and inductor current

I have a question regarding frequency and inductance. What is the relation between frequency of an applied voltage that is square wave, over an inductor, and the average current that would flow ...
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257 views

Torque and Current Frequency Relationship in Lorentz force

Lorentz force equation shows us that current is proportional to the force. Is it safe to assume that the force generated by an AC current at 60Hz will always have the same frequency? In other words, ...
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81 views

frequency and selection of mcu

I am looking at migrating from a MCU of 200MHz to one of a lower frequency/clock speed. Now, I want to justify my action or rather do a feasability study. To explain that my descision to migrate to a ...
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109 views

Disciplining a TCXO from a broadcast reference source

In the UK (and much of europe), a broadcast time and frequency reference is available in the form of the MST radio time signal. This is broadcast using on-off keying on a frequency of 60 kilohertz, to ...
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88 views

Opamp filter cutoff frequency not as expected at higher frequencies

I'm still working on learning Butterworth filters. So far this weekend I went back to school, read about Lapace transforms, poles and zeros, Saleen key design, and finally back to Butterworth filters ...
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99 views

Relation between Digital frequency counter and temperature

This is a homework question, I can normally solve the problems on freqeuncy counter but I never did with temperature related frequency counter problems. A digital frequency counter has these ...
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437 views

Measuring the frequency of a 0-5V signal with DMM and no oscilloscope?

I'm trying to determine whether I can use a DMM to monitor a 0-5V signal of a cam and crank sensor. Both are magnetic. I have a 5V ref. The sensors should vary between 0V and 5V with a short pause ...
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2answers
3k views

independent control of frequency and duty cycle in 555 timer (formulas)

I want to control frequency and duty cycle of output pulse of 555 timer. I searched and find this schematic in a post in SOV but I don't know how calculate frequency and duty cycle in the circuit. ...
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2answers
1k views

3dB Frequency of non-inverting amplifier

The question is The op-amp is described to have that transfer function and I am supposed to find the 3dB frequency of the entire amplifier. Here is what I did I used the fact that 3dB frequency ...
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1answer
50 views

Can I generate frequencies faster than 32 MHz with ATTINY85?

I believe I can use the 64 MHz PLL clock with PWM to toggle every cycle and thereby generate a 32 MHz square wave output on an IO pin, right? Is there a trick to generate an even higher frequency (...
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1answer
47 views

Complex Amplitudes and Exp'l Increase/Decrease

The following are quotes from a textbook, If S(t) is represented as a rotating phasor, the angular frequency of the phasor can be thought of as velocity at the end of the phasor. In particular ...
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79 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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26 views

STM32 simultaneous PWM output with variable frequency and duty cycle

I've been designing a capacitor discharge welding machine for a while, So the working principle is when the button has been pushed, 3 output will initiate simultaneously which 2 of them is variable ...
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48 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 ...
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81 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 ...
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55 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 ...
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41 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 ...
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59 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 ...
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44 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 ...