Questions tagged [frequency-measurement]

Anything related to the measurement of the frequency of periodic signals, i.e. the rate at which their waveform repeats along the time axis. The S.I. unit for frequency is **hertz [Hz]**.

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26 views

What is an equation that will show RF wave characteristics?

I want to show a RF wave on a spherical grid coordinate system. How can I show the RF wave when t = time and y = magnitude? I also want to show curvilinear coordinate transitions of the RF wave ...
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47 views

Crystal oscillator frequency measurement disturbance

I've been building a 10 MHz crystal oscillator circuit (Pierce configuration) followed by a frequency mixer attached to it. The oscillator circuit and mixer are powered by an ordinary power supply. I ...
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Insertion loss measurements, frequency sweep vs measuring points with a constant driving frequency

I have been modelling a surface acoustic wave delay line, and am trying to clarify what I am seeing in the different models and whether this is applicable to what would occur experimentally. In the ...
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1answer
65 views

Measuring the quality factor RLC circuit

I am trying to get the Q factor for this circuit but I don't know how to simulate it properly. I did a frequency sweep from 1 Hz - 30 MHz. The oscillating frequency is 16 MHz. I can't get the ...
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2answers
48 views

How to transform an AC signal of wide voltage to pulses

I want to build a device that measures frequency of possibly different electrical alternators, not having much control of their parameters. For this I need to get digital pulses out of the AC signal ...
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1answer
56 views

How to measure laser class of LIDAR

I just bought a LIDAR with the intention of building an indoors robot that uses it to navigate rooms in my apartment. The manufacturer website states: Low power infrared transmitter conforms to ...
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2answers
34 views

Time Domain and Frequency Domain Amplitudes

I was wondering about these two graphs, the first is taken from an Oscilloscope and the second is taken from a Spectrum Analyzer. Why is the amplitude in the frequency domain close to 1/3 of that in ...
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86 views

Reducing the range of a D flip-flop frequency detector

I'm designing a frequency tracking circuit and I came up with a circuit that tracks frequencies from Fclk to Fclk/2: However, it would be very nice if the bandwidth was a bit narrower, from Fclk to ...
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94 views

wrong frequency of LC based generator with LM311

I have a problem with the frequency of LC meter based on comparator (a very popular solution, similar to this one: http://www.vk6fh.com/vk6fh/lc_meter_vk6fh.htm). I have recreated generator part in ...
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255 views

How to find the frequency of any device? [closed]

Are there devices which can figure out at what frequency every device transmitting radio frequencies operate at precisely? Say from a high of 2.4 GHz microwave to a low of 402 Hz pacemaker.
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602 views

Teaching about LC filters

I'm preparing to teach some people regarding filters, and I'm confused regarding the use of the LC-filter circuit, specifically the circuit below: simulate this circuit – Schematic created ...
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2answers
143 views

Non-intrusive measurement of current and voltage

Sorry if this question is too basic for this forum... I'm an interested amateur but far from a professional. I'd really appreciate information from someone more informed than myself. Hypothetical ...
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4answers
86 views

Frequency Ratio Circuit

I'm attempting to design a circuit that will determine the frequency ratio between a known reference frequency \$f_\text{ref}\$, and an unknown signal frequency \$f_\text{sig}\$. The signal frequency ...
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109 views

Methods of measuring speed of anemometer

I enjoy DIY, but to keep things simple I purchased an anemometer cupset (3 cups). I feel that a magnetic reed switch would get "bounce" at higher speeds and I was thinking of a disk with a slot, and ...
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164 views

Maximum switching frequency

Is it possible to calculate maximum switching frequency of IGBT having only datasheet in hands? https://www.semikron.com/dl/service-support/downloads/download/semikron-datasheet-skm200gal173d-...
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98 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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53 views

Unit conversion: dBμV to dBm, including measured frequency

I'd like to ask for help with conversion of measured voltage V=10dBμV to dBm units. Voltage is measured on frequency ...
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539 views

Is it possible to measure frequency upto 500Mhz with 50Mhz oscilloscope?

Is there a way to measure higher frequency measurements with a 50 MHz oscilloscope (eg rigol ds1054z)? Perhaps some post processing of captured waveforms? Or with the help of some adapters? I have a ...
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236 views

Measure frequencies fast and precise

I need to measure frequencies between 25kHz and 150kHz with a precision of minimum 50Hz. I'm using a MCU 8051(C8051F382 Silicon) with 48MHz clock, and need the measure to be done under 100us, so I can'...
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139 views

Circuit for converting motor tacho-sensor sine wave output to 5V TTL for MCU

I'm trying to measure the speed of a washing machine motor. The motor has a speedometer attached to it, which generates a sine wave with frequency equal to rotation frequency of the motor. I'm ...
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66 views

What are the methods to measure distribution transformer vibration in 0.5g range?

It may seem obvious to use widely available analog devices MEME accelerometer for measurement in range of 0.5g. I did thorough study on this and found out that MEMS sensors either doesn't work or ...
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80 views

Can the frequency of an electrical current be heard and distinguished from other frequencies just by connecting circuit to a speaker?

I have a circuit that I want to be able to detect the frequency of the current going on it (part of the circuit is AC, the power supply is going to be at least 3v, probably 5v, and 6v DC at most). I ...
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2answers
184 views

PIC period measurement sometimes 1 overflow count wrong

Short info: I'm using a PIC18F4580 to measure the period time of two positive pulses using the CCP 1 on the MCU. And then writing the result to an LCD. When testing I sometimes get a result thats one ...
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5answers
623 views

Reciprocal Frequency Counter Mean

I have designed a high precision frequency counter circuit. I am using it to measure a frequency of around 35kHz that is stable to 0.1mHz. I can measure the frequency using a Stanford Research Systems ...
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113 views

Frequency Counter Problem

I'm a Electrical Engineering Student and i have to respond to this question before I can do the lab work. "A frequency counter with an internal 1MHz oscillator and six frequency dividers is given to ...
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1answer
193 views

Enabling external reference to HP/Agilent Signal Generator (8648C)

What is the proper way to use an external 10 MHz clock signal for an HP/Agilent signal generator (in my case: 8648C)? With my Tektronix, Rohde & Schwarz devices, internal/external reference has ...
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2k views

LTSpice: How to use .meas command to find the fundamental frequency of non-sinusoidal signal?

I want to find fundamental frequency of a periodic signal (non-sinusoidal) in certain time window using the .meas command in LTSpice. I was using the following ...
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357 views

Simple way of measuring RPM of motor by How to make Frequency/Pulse counting circuit

I want to measure RPM of a motor. For this, I am planning to put an assembly where an IR LED facing with IR sensor under line of sight. With every rotation, the line will be cut once - and hence the ...
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1answer
71 views

Grounding oscilloscope probe effects

I have built an active band-pass filter on a breadboard with the use of an MC33078p op amp. Gain is 32 on paper. When I apply the AC signal to the circuit, 18.1mV P-P and 660kHz, the oscilloscope ...
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4answers
392 views

Differential Amplifier's Unusual Behavior

This circuit is made of one differential BJT transistor pair and voltage-amplification stage with negative feedback. simulate this circuit – Schematic created using CircuitLab About this ...
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3answers
211 views

Is a 0.01s time base really useful in a frequency counter?

I am currently designing a frequency counter based on the PIC16F628A. It is working as expected but I would like to add some useful features. According to the images found by googling, I noticed that ...
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138 views

Measure duration of a non periodic message on FPGA with VHDL

I'm trying to measure the duration of a non periodic signal(message) on FPGA, as below : I want to measure the duration of the measured signal by counting the number of reference clock's period. I ...
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415 views

interfacing tcs3200 color sensor with STM32f746zg

I want to interface TCS3200 color sensor with STM32f746ZG. Since the TCS3200 outputs a frequency based on the amount of light received, I need some way to count the number of pulses for different ...
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296 views

How are high-speed circuits tested if test equipment doesnt exist?

How was testing done for Ghz to THz range circuits and devices before fast enough scopes and frequency counters existed?
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263 views

Count based frequency meter

I'd like to understand how a frequency meter treats a sine wave, i think i got it, but still I'd like some confirmation. So i was taught with square signals where the meter counts the impulses in a ...
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123 views

What's the difference between measurement resolution and digits per second in time measuring devices

In time/frequency counters/analyzers in technical specifications you can almost always find resolution and digits per second values next to each other. What is the difference?
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2answers
792 views

sampling rate and frequency response of a vibration sensor

I am trying to measure the vibrations of a lathe machine using a piezoelectric accelerometer sensor. I want to know if the sampling rate can be set at a value greater than the flat response frequency ...
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1answer
518 views

how to measure phase response of filter

I have a lowpass filter (0 - 2MHz). I wanted to measure the phase response but I am a little bit confused. I have a signal generator and oscilloscope. Any tips how I could accomplish that? Edit: ...
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89 views

How can i convert an AC output from an outlet to a digital signal? [closed]

I´m making a digital frequency meter and want to compare the frequency from an outlet with a stable 1hz frequency from a crystal using an AND logic gate. However, I´m not sure how can i get a digital ...
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259 views

incorrect i2c frequency?

I am using an ATTiny88 MCU as master over an Si4012 slave. The MCU is running code produced by Arduino IDE. Connecting a logic analyzer to the SCL and SDA lines produce an output as below - second ...
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255 views

How to measure frequency of AC Voltage(In range of 0.05-5v) using micro-controller?

I have one sensor which outputs in the range of 0-5v AC voltage and I want to measure a frequency of this signal using the microcontroller ? Is there any IC which gives digital pulse in output when ...
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1answer
224 views

Trying to understand how to design the gate of a frequency counter

I´m trying to design a frequency counter for my physics class. My teacher demanded that we build it using a 32768 Hz crystal and 4060 ic. In my research i stumbled across this design: I don´t have a ...
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1k views

Digital Multimeter not working on higher frequency

I have an ordinary multi-meter which looks like the one below in the description. When i measure higher frequencies above 200kHZ the voltage is not showing up properly as it says on the frequency ...
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2k views

Why is 30MHz Clock signal distorted on oscilloscope?

I'm trying to probe a 30MHz clock signal, coming from an FPGA and routed to a CCD sensor. There are no other components, other than connectors, between source/destination. When I probe this signal ...
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1answer
232 views

an/prm-10 grid dip question - how the voltage can be negative at the grid? [duplicate]

I am trying to repair a recently bought AN/PRM-10 grid dip. I have replaced some electron tubes by new ones and (almost?) everything seems to be OK regarding the voltages at the pins of the electron ...
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1answer
497 views

Designing a senvitive frequency to voltage converter

I need to make a battery powered frequency to voltage converter that will monitor very minor frequency changes, around 100Hz with base frequency of 3-5MHz (may vary during operation); something like a ...
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500 views

Crystal Oscillator Design and “Crystal Drive Level”

I followed the video at the link http://www.analogzoo.com/2015/07/ . The video directs watchers to a tool at http://www.analogzoo.com/lab/pierce_bjt.html to help determine parameters to cause ...
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3answers
112 views

1-11 Hz to DC voltage signal

I'm doing an internship where we are connecting all kind of sensors on a CAN-network for an automated datagathering. There is one sensor that sends a 50% duty cycle frequency signal between 1 and 11 ...
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4answers
2k views

Does a BNC splitter introduce defects into the signal?

I'm currently doing some contract work that includes finding and recommending a signal generator model for frequency measurement device verification. The verification scheme requires generating a ...
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190 views

Overtones Produced From Speaker Load on Asymmetric Square Wave

What I am doing I built a circuit using a 555 timing chip in astable mode which produces a square wave. There is a potentiometer which allows me to adjust the frequency produced. One aspect of this ...