How many times something happens per second, measured in Hz (hertz).
Questions tagged [frequency]
1611 questions
33
votes
3 answers
Negative frequencies: what is that?
I know that when the frequency is 0, the voltage will be pure DC. But in DSP and Digital Communication, I have seen mentioning of negative frequencies which I dont quite understand. For example, like \$ -f_{0}\$ to \$ f_{0}\$ frequency range. How…
0xakhil
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4 answers
What is Frequency in electronics?
This has been floating in my mind for a while, everything has a frequency. Like a dc-dc converter, my scope is 100 MHz(i know that's a bandwidth but it has the unit of frequency). I understand that an Astable 555 has a frequency which is the mark…
Dean
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7
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3 answers
What happens to RLC circuits at resonance frequency, conceptually
What occurs when $$\omega = \omega_r$$
The circuit frequency equals its natural frequency? So what. And why is it important?
40pro
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7
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What is the unit for resonant frequency?
What is the unit for resonant frequency? where \$\omega_0 = \frac{1}{\sqrt{LC}}\$? Is it just \$HF^{-1}\$?
azza
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Frequency Reuse Patterns
In Multiple Access Protocol for cellular networks, there is this Frequency Reuse Patterns. And I am given a formula to one of the patterns that states: \$\text{Reuse factor }\mathbf{K} = i^2+j^2+ij\$
I know that the reuse factor \$K\$ meant the…
xenon
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6
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2 answers
Low "Hum" Frequency Detector
How do I create a frequency detector that can detect low "hum" sound? (quite low frequency sound probably made by a air-con or similar type of machine)
Please feel free to ask me questions if my question is unclear.
Larry Morries
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6
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2 answers
4 Hz Stable Frequency generator
Whats a good circuit/design that will generate a very stable 4Hz signal (to feed into a counter) that won't drift with temp / time.
It's not so important that its exactly any particular frequency, just around 4Hz, it's just important for it to stay…
Keith Nicholas
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5
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2 answers
Astable multivibrator with increasing frequency
I am wanting to design a circuit that uses an astable multivibrator as a clock source. However the difference being that over time the clock is gradually sped up until it reaches some multiple frequency.
I have found circuits that have a speed that…
jme
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4
votes
1 answer
How does this identification card work?
My father recently brought home an old identification card, and after cracking it open I found that it consisted of simply a large coil of wire, connected to a small electronic chip (which was so small that I sadly lost it - it looked something…
Joshua Lin
3
votes
3 answers
Being Above Resonance
What does it mean being above resonance?
Does it mean that our frequency is more than the resonance frequency?
In an LC circuit, why is circuit more inductive when frequency is above resonance?
user34424
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3
votes
1 answer
mirror in frequency domain
Why is that in the frequency domain, I always see mirror images? What causes these mirror frequencies to appear? How do they pop in? Where do they come from?
Secondly, what is this concept of negative frequency? In normal life, most of the time I…
vvavepacket
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Calculate maximum deviation of quartz crystal
How can I calculate the maximum deviation of a quartz?
This is from datasheet (12MHz):
Frequency Tolerance at +25° C => +- 30ppm
temperature tolerance -20°~ + 70°C => +-50ppm
aging (first year) => +- 2ppm
I want to calculate the maximum deviation…
otto
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3
votes
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recording low frequeny using sound card
I'm trying to record heartbeats and breathing (movment of the chest) using the pc sound card. I've seen alot of application where they record heartbeats, but none discuss the breathing. I know that most sound cards block low frequencies to eliminate…
Isra
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3
votes
3 answers
Drawbacks and Benefits of High Switching Frequency
I was reading about Benefits of High Switching Frequency, I found the following:
Smaller converter can be cheaper – up to a certain power output. Beyond that power level small size might be worth some added cost.
Transient response can improve with…
Joe
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3
votes
2 answers
Can I measure the -3dB point of a wireless link with a lower frequency?
What I want to do is measure the bandwidth of a wireless video transmitter. I know for a fact that this is going to be at least 8 MHz if not much more as it gives a good video image with an OSD which has a pixel clock exceeding 4 MHz. (I'm trying to…
Thomas O
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