The frequency-measurement tag has no wiki summary.
2
votes
1answer
78 views
555 timer monostable time constants
When making an monostable circuit with a 555 timber, the time that pin 3 is on is calculated using this:
time on = 1.1 x R1 x C1
My question is why is 1.1 included.
2
votes
1answer
66 views
555 timer astable time constants
When making an astable circuit with a 555 timber, the frequency of pin 3s pulse is calculated using this:
f = 1.44 / (R1 + 2R2) x C
My question is why is 1.44 included.
-4
votes
2answers
207 views
How can i know the frequency range of electronic device?
How do I know the frequency of an electronic device? For example, we all know that the microwave is working under 2.4 GHz frequency. So, if I want to know the other frequency range for other devices, ...
3
votes
1answer
156 views
AVR Measuring frequency using external interrupt - where are my cycles going?
I'm using an external interrupt to measure the frequency of a signal, the AVR clock is at 8MHz. I'm essentially counting the ticks between pin toggles using a 16 bit timer (with some handling for ...
0
votes
2answers
283 views
Frequency measurement with STM32
This question is mainly a query for an advice.
I am trying to implement a frequency meter on STM32F4.
Up to this point I have a working ADC converter with DMA and a timer which checks for the current ...
2
votes
2answers
72 views
How can I improve my Freq to Voltage circuit?
I had a term project which was based around Analog-to-Digital convertors.
We used anLM2907 Freq-toVoltage convertor to take a 150mVpp sine wave (0- 1kHz) and convert that to a voltage. The voltage ...
1
vote
1answer
222 views
Estimating a sinc period and width of a rectangular pulse
For a rectangular pulse that has as a fourier transform of a sinc function like so:
How can I estimate its sinc period in the frequency domain and compute the width of the rectangular pulse in the ...
0
votes
1answer
517 views
Frequency to voltage converters [closed]
I'm looking for a frequency to voltage converter IC that can operate with an input frequency of around 500 kHz. The device does not have to be high-precision and the operating voltage can be anything. ...
1
vote
2answers
333 views
How to observe powerline modulated signal?
I was assigned to observe the modulated signal of a PLC modem, but I have not really started yet. How do I do this? Should I use an oscilloscope or spectrum analyzer? If so, do I just connect it to ...
9
votes
6answers
1k views
Measuring frequency of a signal above 5V with a microcontroller
I want to measure the frequency (up to 300 Hz) of a rectangle signal, that varies between 0V and Vtop, where Vtop is anything between 5V and 15V. Because I cannot apply more than 5V to the ...
2
votes
1answer
240 views
counter giving erratic results for frequency measurement using Atmega32
I am using a photosensor which gives output as a square wave. The frequency of this square wave is being measured using Atmega32A with 1MHz clock. The full scale output of sensor is 500kHz.
The ...
1
vote
0answers
122 views
power supply frequency response
I have a question regarding the frequency response of a boost converter. I am curious to know what causes the "blip" at around 8kHz that causes the response to go up and then back down. At first, I ...
3
votes
1answer
211 views
output filters for power supply design
I am trying to develop a design for a power supply design. At the output of my design is a diode rectifier with capacitive filter output. I've been told that I should expect to see an ESR zero or ...
4
votes
2answers
1k views
Problem with a Relaxation Oscillator (using Op Amp)
I'm studying a relaxation oscillator. This wikipedia circuit shows exactly my circuit with the only difference that I'm using different values for each resistor.
I called resistor R the one ...
2
votes
1answer
180 views
Analog Telephone Frequency Response Curve
Old analog telephone circuits using carbon microphones seem to be said to have a frequency response of, from various low frequencies which differing reports put at between 275 Hz and 400 Hz, up to ...
6
votes
1answer
2k views
How to measure pulse width of an IR signal using an 8-bit PIC?
My friend and I want to design a universal learning remote controller, like this one, for learning purposes. What we want to do basically is store and replay infrared pulses.
We want to detect 36kHz, ...
0
votes
2answers
117 views
Testing Oscillator Over Temperature
I want to characterize the frequency inaccuracy of several silicon oscillators over temperature to see which one will work best in my end application. If I populate the oscillator on a bare-board and ...
1
vote
2answers
399 views
Counting DC power pulses per minute
I need to implement a frequency counter (pulses per minute) of a DC circuit that goes up to 20 volts. A little background, I am building a linear power supply 0-20 volts, 0-3 amps for my relative who ...
4
votes
1answer
2k views
How to correctly simulate a simple LM2907 circuit in LTSpice?
I'm trying to convert the frequency of a 0-5V square wave, which ranges from 0-20kHz, to a voltage using a simple LM2907 (8 pin) circuit.
Using R1 as 100k, I've calculated C1 to be 416pF for a ...
2
votes
1answer
367 views
Measuring Frequency Shift
A previous question on doppler shift velocity sensor make me ask this question. @Chris_stattron provided an insight but I was too curious to leave it at that comment hence the question.
Assume, I am ...
10
votes
3answers
4k views
Oscilloscope Bandwidth, what's it all about?
This question popped up to me a few moments ago.
I was measuring what is intended to be a 50Mhz square wave of level 0 to 2.5, however what I saw on the screen is a sine wave that was centered around ...
2
votes
2answers
426 views
Analog Max Frequency Detector Circuit
As a follow up to this question: How to sample audio at Nyquist frequency with MSP430F5438?
What type of circuit would I use to generate something that a microcontroller could use to determine the ...
7
votes
7answers
5k views
Measuring 0 - 1MHz ( 0.25Hz resolution) Squarewave using an MCU
I need to measure the frequency of square-wave that can vary between 0 and 1MHz, and has a resolution of 0.25Hz.
I havent decided on which controller yet but It will most likely be one of the 20pin ...
