# Tag Info

10

The amplitude distortion plot you showed is in dB, dBV specifically (dB's relative to 1 V). So you need to take those dB values and covert them into volts before putting them into your formula. For example, -67.363 dBV is 0.000428 V (RMS) (using an on-line calculator). You should be able to take it from here.

6

If you want to treat this signal as a periodic one, then you can take its Fourier series. Unlike most other periodic signals, you have free choice of what frequency to consider as its fundamental frequency --- you can calculate the series for any fundamental frequency But regardless of which fundamental frequency you choose, you'll find that all the terms ...

5

I like your thinking on this. You see something about it that bugs you so you ask a question. Those little things that bug you because they don't fit, and the curiosity to pursue them are very positive traits in engineering and science. But I think you are mixing up a few different motor types. Induction motors are the ones that have slip. If you run an ...

4

To start with, just think about a classical DC motor, one with brushes. It is operating at some speed and the load requires some torque to operate at that speed. The mechanical power required to drive the load is speed multiplied by torque. Some voltage is applied to the motor and the motor draws some current. The power into the motor is current multiplied ...

3

[EDIT: I failed to mention that by "frequency", I'm referring to how DC motors can be controlled with pulse width modulation, and those pulses go in at some frequency. Otherwise it wouldn't make sense to talk about "frequency" with direct motors] PWM frequency has no direct effect on motor operation, it is effectively the same as the equivalent (...

3

Take a Frequency Modulated (FM) signal going into a superheterodyne receiver which has a tuning range over 88 to 108 MHz. Any given FM signal will occupy a much narrower bandwidth than that. Typically an audio signal will deviate the carrier, that is modulate the frequency, by around +/- 100 kHz. If we take the carrier to be 95 MHz, then the complete signal ...

2

I think the question includes a contradiction, the frequency serves to explain the periodicity of a signal in the frequency domain. Then in case of non-periodic signals we use the term bandwith that is the term that indeed that book used, at the end of the paragraph it says, quoted "The bandwidth needed is 5.5124 MHz". The signal shown is simple so most ...

2

What you're making here is called a relaxation oscillator. Here's a reference for that: http://www.analogzoo.com/2015/01/relaxation-oscillator-design/ The summary for a basic calculation: Charge / discharge time is the time constant which is 1.1*RC. Period is twice that, or 2.2*RC. For frequency we get 1/(2.2*RC) Some items to check and/or fix in your ...

2

There are three ways to improve your resolution. Whether that translates into accuracy depends on your reference. You may or may not need accuracy. If you're prospecting for buried ferrous objects, then you only need to detect change over small distances and timescales, and you'll get away with a modest reference. If you want to detect changes over long ...

2

The problem is that the code is counting how many pulses happen during the measurement period. If you measure for 1 second, you have 1 Hz resolution. For 0.1 Hz or 0.01 Hz resolutions you need to measure for 10 or 100 seconds. The other way to calculate this is how much time it takes between pulses, or between 100 or some other amount of pulses. The MCU has ...

1

Frequential analysis is normally taken in the context of integral transforms with complex exponentials - such as Fourier and Laplace - which can alternatively be explained as infinite sums of trigonometric functions, with varying phases and amplitudes. The only frequency value $\omega$ that will allow you to represent a constant with a trigonometric ...

1

The type of problem you are talking about might be be explained by an induction motor. In a dc motor increasing the no of pulses would only increase the average voltage which would then lead to motor entering a transition state till the new steady state is achieved(if achievable). If a steady state is achieved in accordance to both load and motor torque the ...

1

As it's homework, we do the Socratic method here. How fast does the capacitor round U8B slew? When it's going +ve? When it's going -ve? So how long does it take for each slew? What voltage is the slew coming from? What voltage is it going to? How do the values of R1 and R2 affect those voltages? How does the length o time slewing relate to frequency? ...

1

I went ahead and looked at your video. The coil you are using will look pretty much like a short circuit at audio frequencies. You are quite simply putting too much of a load on your amplifier. Diodes will not help. You need a coil with far more winding on it if you want to continue using an audio amplifier to drive the coil. I used this calculator to ...

1

Picture taken from this site For this basic design you have to use an odd number of inverters to get negative feedback at DC and thus the circuit becomes self biased.

1

You have to use the Fourier transform. But Fourier transform is for a continuous time-domain signal. But when you will measure a signal using ADC you will get a discrete time-domain signal. Then you will need to do DFT (i.e. Discrete Fourier transform). There are several ways to find the DFT sequence. The algorithms are commonly known as FFT (Fast Fourier ...

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