# Tagged Questions

A signal is a stream of information in the form of a varying quantity. Usually in electronics, signals can be in the form of voltages, currents, or radiated electromagnetic fields.

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### Signal representation in frequency domain

My teacher taught me that the frequency representation of time limited signal will be band unlimited. Also the frequency representation of time unlimited will be band limited. i.e frequency domain ...
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### What is maximum range of voltage measurement?

Another 'Basic EE' question here (from a mathematician). Being rather ignorant of the matter - I would hazard to guess that there is some physical limit to the range of voltages that can be ...
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### How to measure the signalling speed of Gigabit optical ethernet?

Signalling speed of Gigabit Optical ethernet is 1.25 GigaBaud . I tried some methods such as measuring the UI of the eye diagram on a sampling oscilloscope by sending some random test patterns , high-...
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### Telephone connected signal [on hold]

When we dial a number after the reciever pick up a counter starts it means a signal from the center has been sent to our telephone or cell phone. I want to now what is that signal (frequency , time ...
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### PNP transistor instead of mosfet to register small clock and data signals [on hold]

I have a device that outputs -0.2v clock and data pulse (It works on CR2032 (3v) and I assume it's CMOS), I want to register that signals on arduino in simpliest way. Since no mosfets have threshold ...
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### How a signal is transfered with only one connection in a simple circuit [closed]

I need some explanation to something i experience. I use an Arduino (DUE) to create some audio waveforms, and a laptop as an oscilloscope to watch the waveforms (and for programming - powering the ...
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### Channel Capacity Clarity needed

1) Suppose a Noiseless Binary Channel, who's input is reproduced exactly at the output. Let X be the transmitter and Y the receiver (i.e (X=0----->Y=0 and X=1-----> Y= 1)) I understand intuitively ...
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### Up/Downconverter issues

I am having some issues with my up and downconverter. What I'm trying to do is to receive a 125 kHz signal, upconvert it to 433.125 MHz, transmit it, receive that signal, and downconvert it back to ...
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### Improve Rise Time on 1Hz Signal

I am using a MCP79410 real time clock to generate a 1Hz square wave signal (50% duty cycle) for a low power display (Sharp Memory LCD). Without this signal charge builds up and the pixels show burn-in....
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### What does an “ac coupled signal” mean?

I've heard this term many times from many different sources, but none of them gave me a definition. Here is my understanding: "coupled" means "connected together". If two circuits are "capacitively ...
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### 3.5 mm male to RS232 male : wiring problem

I am trying to use an old datalogger thermometer (Tenmars, TM-747DU-4 Channel Datalogging Thermometer, Webpage link) which has a 3.5mm female connector (audio connector). The wire supplied with this ...
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### Design of 3g signal repeater [closed]

I am interested in 3g signal repeater and decided to design one. I am planning to just buy 2 antennas and design the amplifier circuit only. my questions are: Should I care much about the antennas? ...
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### Coaxial Cables: RG6 or RG6 Low Loss?

I have a 50 foot zBoost RG6 low loss coaxial cable and it's not long enough for what I need. I need a 100 feet of cable (that will work outdoors) and I'm stuck between a rock and a hard place in ...
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### Temperature sensor output signal to TTL

I'am looking for a circuit schema to convert 0.5V square signal from 2-6 kHz into square signal of 5V on output side. What I need is to count / measure frequency with microcontroller. I have a SEABIRS ...
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### Signal conditioner for a piezoresistive pressure sensor

I have an instrumentation amplifier which output voltage equation is given.The piezoresistive pressure sensor in Figure E3.12 consists of a bridge of four silicon strain gages of 4000 ohm and 1 mV ...
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### Can you measure voltage along a wire a multiple points simultaneously?

Basic EE question here. Suppose I have a piece of wire a foot long. Suppose there is some signal (for example a clock signal) going through the wire. Is it possible to simultaneously measure the ...
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### analog filters- dispersion, ripple and windowing

What is the adventage of using a rectangular window instead of hamming? Is it necessary to minimize the ripple in the pass band or in the stop band? If I put a periodic signal through an analog filter,...
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### Finding UART pins on a PCB header

I have a PCB with some headers exposed. I know for certain that some of those pins are UART connections (RX,TX, Ground). I'm hoping to find RS232 with TTL voltage levels but this is just an assumption....
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### What is the type of the wifi interference to ZigBee? Multiplicative or additive?

As we all know, the cross technology interference is a critical problem. CTI means that different communication technologies operate on the same spectrum (e.g., 2.4GHz), and this would lead to the ...
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### Type J Thermocouple Signal Conditioning to 0-5V

I've been working with signal conditioning, thermocouple out specifically. I'm working with a span of 450 °C, that is, from -50 °C to 400 °C. For those values of temperatures I get, according to the ...
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### Generate +2V Offset on a +12VCD Supply line

I have a 12VDC @50mA_Max supply line. I need to inject a +2V 50us offset pulse to the +12VDC line, having an effective +14V for 50us. I have access to an external power supply, where I can have ...
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### “Tagging” Data traveling over serial port?

If I'm reading data from multiple channels (UART) of a microprocessor, but I want it to be continuously read, I imagine the logical thing to do would be to cycle through the channels and output data, ...
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### one-way RF signal diode

Is there a special diode or band pass filter that will only allow RF signal to go though a wire in one direction like a diode does with electricity?
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### RS 422 signal voltage booster

I have RS422 output signal with 2.6V peak to peak, However after distance 25 meter this signal voltage is attenuated upto 0.8V and receiver is not able to detect signal. Is there any IC for boost this ...
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### How do I stop coiled (telephone) wire blocking signal?

This circuit is working just fine if the output signal uses a straight wire, even if it is a very long wire with say a 1K resitor added to the end of it. However, the signal does not get through when ...
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### How can I create two ac signals with a voltage controlled phase offset?

Is there a fairly straightforward analog circuit (resistors, capacitors, transistors, etc) to generate two sine waves of the same frequency and introduce a relative phase offset between them? So I'm ...
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### What is a typical value for the gain of a smartphone's Bluetooth (or Wi-Fi) antenna? [closed]

I can't find specific values for transmitter and receiver gain anywhere. Very often the Bluetooth module is together with the Wi-Fi module, so a Wi-Fi antenna gain value will help me as well. I need ...
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### How to read out data from this moisture sensor?

I found a cheap moisture sensor on Ebay that only came with the schematic attached. The moisture can be read with an analog or digital signal. However, I am wondering how the opamp creates a digital ...
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### Falling edge detector using BJT

I'm trying to build what is basically an electronic push button switch - something that would switch an led on an off with the same signal . I figured doing this would require a falling edge detector ,...
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### What is the source of this shape on my USB eye diagram?

I have designed a USB device around an STM32F105. It is USB 2.0 Full Speed CDC device configured as a Virtual COM Port using ST's USB Library. It uses the STM32's built-in PHY, and runs at 12 Mbps. ...
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### What is the difference between the terms wave, waveform, and signal?

What is the difference between wave, waveform, and signal? Or do they have the same meaning? Can they be used in place of one another?
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### Lengthening button press signal

I'm trying to rewire an arcade game, and I need one button (a simple microswitch hooked up to the coin acceptor) to have a longer press than a coin passing by provides. I'm not sure exactly how long ...
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### Resonant RC Series and deriving equivalent circuit

How is it that this is equivalent? Assuming all transients have died out. vi = Vcos(omega*t) The fake input was defined as: v_{cp}^\sim = \frac{V_i}{1+j\omega_1RC} e^{j\omega\\_1t}...
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### Small signal equivalent circuit BJT question

This circuit is two BJT transistors in so called 'darlington configuration'. I want to analyse this circuit for AC signals (where the capacitors are shorts). The question is to calculate Delta_V_L/...
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### Simulink how to convert Duty Cycle to reference voltage signals(Uref)

In Simulink I am creating a DC-DC buck converter using Average-model based VSC Universal. But one input of VSC is in Uref. For this case I need to convert Duty Cycle (D) into Uref for Input. Because ...
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### Wireless 2.4GHz to Bluetooth? [closed]

I've been wondering about this for a while; I have a Wireless 2.4GHz keyboard that requires a USB reciever to catch the signal. How great would it be though if I could use it on my phone, for ...
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### 12-bit output to +/- 10v

Suppose we have a signed 12-bit output which is capable of representing both positive and negative numbers, how can this be converted to a +/- 10v signal using DACs, op-amps, etc. For example, 1100 ...
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### How do I determine the start and end of the wave?

I am facing a bit of a challenge in trying to understand basic concepts or terms within the signal world. I have a number of values retrieved from a sampled signal that is generated randomly for no ...
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### Using an earthed function generator with an earthed oscilloscope and ground loops

I have a function generator and I noticed that its DC GND is internally wired to its earth pin. Similarly I have an oscilloscope and I noticed that its DC GND is also internally wired to its earth ...
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### Lock-in amplifier output to spectrum analyzer

In several lock-in amp tutorials and experiments (including at the end of “Physics 111: Low Light Signal Measurements” on Youtube), the lock-in amp X or Y output is applied directly to a spectrum ...
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### Analog signal vs. Alternating current

I am seeing that both of the analog signal and alternating current is represented by the same graph: As far as I think I know, an alternating current travels back and forth with gradual changes in ...
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### Actual procedure used to establish a MW link budget in telecom?

If it possible can someone share with me the actual procedure used (Not the theoretical steps in book !) like in Huawei or others telecom vendor to establish a Microwave Link between to sites Like ...
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### In a Delta-Sigma ADC, does noise shaping bring the noise to the signal's frequency?

I'm trying to understand the Delta-Sigma ADC. It is known that it pushes the quantization noise to be in the higher frequencies (noise shaping). Since I don't quite understand how this works, I ...
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### 3.3V to 5V logic converter using p-channel mosfet

I am trying to convert a 3.3V logic signal to 5V logic signal. I am using a p-channel MOSFET and I can not get it to send the full 5V signal through. Below is the circuit I am using.
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### Low pass filter for differential signals

I'm building an adc and amplifier circuit for sensing a differential signal out of a pressure sensor. My plan is to use a circuit very similar to what is seen below: The total differential output ...
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### Determining Sampling Rate of Analog Signal from Modulated Signal

I'm studying for a final and have a question. The image above contains a graph of time and signal duration. I'm used to seeing the PWM/PPM/PCM/etc rather than this type of graph. Am I correct in ...
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### Problem with implementation XAPP495 [closed]

I'm working on XAPP495 to show a signal which is throughput of a HDMI signal from my Laptop I do this steps: created a new ISE project added all of the .v files from XAPP495 added dvi_demo.ucf set ...
Determinate the power of the discrete signal: $$x[n] = u[n] + (-1)^n + (\frac{-1}3) ^n * u[n]$$ where: $$u[n] = \begin{cases} \ 1, & n \ge 0 \\[2ex] 0, & n \lt 0 \end{cases}$$ The answer ...