How many times something happens per second, measured in Hz (Hertz).
4
votes
1answer
887 views
Required Bandwidth for ASK
In Amplitude Shift Keying, the bandwidth required is given by \$B=(1+d)S\$ where B is bandwidth, S is the signal rate, and d is a value of either \$0\$ or \$1\$.
But how could the required bandwidth ...
1
vote
2answers
2k views
Relationship between sampling rate and number of levels/bits in PCM
It is said in the books that increasing the levels of quantisation codes in Pulse Code Modulation, or in other words increase the number of bits, could give a better signal.
I understand that having ...
2
votes
3answers
244 views
Where should an increase in harmonic frequencies go in the Nyquist formula?
From the Nyquist formula that \$ Capacity = 2 \times Bandwidth \times log_2(L) \$, where \$L\$ is the level the signal represents, the total number of possible bit combinations the signal can ...
2
votes
4answers
1k views
Why all digital signals have infinite bandwidth?
Why digital signals have "infinite bandwidth"? Frequency is the number of cycles per second. I have seen before the formula that bandwidth=Maximum Frequency - Minimum Frequency. I remember I was told ...
-1
votes
1answer
317 views
What are Discrete and Continue Frequencies?
When it says "Periodic Digital Signal is composed of periodic composite analogue signal with infinite bandwidth with discrete frequencies" and "Non-periodic Digital Signal is composed of non-periodic ...
4
votes
3answers
1k views
Interview Question, what's limiting the output frequency for the FPGA circuit?
I recently received a question in an interview that partially stumped me. It went something like this:
You have an FPGA circuit that is supposed to be generating a signal with a frequency of 500MHz, ...
3
votes
3answers
222 views
Reading frequencies without filters
Is it possible to read a set of frequencies with a PIC in such a way that for each frequency a different function is called?
The idea was to send multiple frequencies at different times (no ...
5
votes
2answers
251 views
Injection locked frequency dividers
I am beginning to design a monolithic frequency synthesizer (around 2.4GHz) in which I need the maximum of spectral purity. I was looking at injection locked frequency dividers (ILFDs) for use as a ...
1
vote
2answers
848 views
Highest ADC input signal frequency for atmega8?
I am trying to make a simple project which involves acquiring some data from the adc of atmega8 chip and then sending that data to UART. But I cannot figure out what would be the maximum limit of the ...
3
votes
1answer
147 views
Binary Counter and an Oscillator for frequency generation
I'm interested in creating low frequencies using a high-frequency oscillator. For example - using a 12Mhz oscillator to create 1Khz, 2Khz waves.
I've been said that using a Binary adder(oops) counter ...
1
vote
1answer
192 views
At DC frequency, how long can wire be until signal attenuates almost completely?
Just got curious about this last night when I was wiring a couple of LEDs on my brother's long board.
For a simple DC circuit (Battery, resistor, LED), how long can I stretch the wire until the power ...
14
votes
3answers
823 views
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 ...
7
votes
1answer
409 views
Characterization of bypass capacitors
I was reading through a few post including Decoupling caps as well as this app note Xilinx Power Distribution Network.
I have a question regarding capacitor values within a power distribution system. ...
4
votes
2answers
420 views
Odd number frequency divider
Important note: You are not helping me do my homework. This is for a competition for engineering students, that encourages you to "use your network" ;)
I've got this pattern for a frequency divider ...
2
votes
3answers
129 views
Speed of various prototype systems for digital electronics
I would like some advice on what digital signal frequencies I'd be able to work with for hobby projects.
I asked this question recently about interfacing to a memory chip from an fpga as a hobby ...
1
vote
0answers
102 views
Dynamic Frequency Scaling in Renesas M16C
I am working on a research project that involves implementing a dynamic voltage and frequency scaling for Renesas M16C microcontroller based system.
I am working on BNS QSK62P+ development board. ...
0
votes
2answers
114 views
How can we detect the source of the radio emission?
if someone is generating frequency, can receiver detect from where exactly it's emitting? If someone is emitting on illegal frequency band, how it can be caught?
1
vote
1answer
619 views
Setting correct operating frequency for LLC resonant SMPS
I need to figure out if an LLC half-bridge resonant SMPS is designed (more or less) correctly. I am not an SMPS designer, and neither is the manufacturer, so I'm just reading a bunch of app notes and ...
6
votes
4answers
3k views
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 ...
2
votes
5answers
321 views
why cannot generators having different frequencies supply in the same transmission line?
I am thinking of the issue that
the TEPCO electric transmission
networks cannot be taken over by other
electric companies because of
frequency difference.
TEPCO is the electric company ...
6
votes
2answers
611 views
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, ...
2
votes
2answers
106 views
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 ...
1
vote
1answer
351 views
Schematic for 4-band stereo equalizer?
I wand to make a simple stereo 4-band EQ for a mid-fi amp I'm building. I draw my knowledge from this excellent article - however, it only seems to talk about peak/notch bands and not low and high ...
2
votes
1answer
264 views
frequency generator / counter
I want to generate a precise frequency in the 500MHz range, and have therefore purchased a VCO (200MHz to 400MHz).
To measure the VCO output frequency, I'm trying to build a high frequency counter up ...
1
vote
1answer
153 views
Can the frequency of the SPI sck on an mbed be adjusted?
I'm trying to control a serial dataflash memory through the SPI interface of an mbed. SCK from the mbed is connected to CLK of the dataflash memory. I'm not sure, but I'm starting to suspect that this ...
0
votes
3answers
247 views
Frequency Transmitter
I was wondering if anyone had any site or diagram for a cheap (and preferably small) for a circuit for a 60 to 80khz frequency generator.
1
vote
4answers
612 views
Can a cheap, low bandwidth, long-distance wifi be physically and electronically possible for public use?
Since facebook and all the social media warfare, I have realized that the internet is awesome, but not very scalable to embedded devices: new generation network standards are still expensive to make ...
4
votes
3answers
3k views
3-phase Motor Speed Controller
Background
If you look at my profile description, you'll see that I'm involved in building and wiring up Carnival floats that are powered by an 800KVA, 415v, 3 phase Generator. Electrically, they ...
1
vote
4answers
114 views
Frequency Filtration
I have a signal that consists of N frequencies all with unknown phase and frequency(N) = frequency(N-1) + 2Hz. I would like to selectively scale the amplitudes of some of those signals in such a way ...
3
votes
4answers
2k views
Connecting piezo buzzer with BJT
I have a 4 KHz piezo buzzer and a microcontroller (arduino) that outputs that 4 KHz from one of it's pins. All is fine if I connect the buzzer to the output with one pin and to the ground with ...
10
votes
2answers
450 views
Frequency ranges that causes a hazard to humans
I hope many people might feel little awkward to see this question. But I feel this is important. Because in my place where I am living I can get a radio (Audio Receiver) very cheaply. I don't know ...
8
votes
3answers
2k views
How critical are UART frequencies?
I'm going to be using an 8 MHz crystal to run my microcontroller at 16 MIPS (PLL 4x, 2 cycle instructions.) However, 8 MHz doesn't divide into any UART frequencies AFAIK... so how critical are these ...
18
votes
4answers
2k views
Why does a faster clock require more power?
If you overclock a microcontroller, it gets hot.
If you overclock a microcontroller, it needs more voltage.
In some abstract way it makes sense: it is doing more computation, so it needs more energy ...
7
votes
2answers
614 views
Is it true that the power line frequency is kept accurate by atomic clocks?
I've heard rumors that the power line frequency is kept stable and accurate by syncing it with atomic clocks. Is this true? What kind of accuracy does it have? Is this true everywhere?
3
votes
3answers
281 views
Lowering PIC Clock Frequency
How do I lower the clock frequency of a PIC18F2550 and recalculate the peripheral dividers?
I'm trying to make it run cooler. Currently, it runs at 12MIPs/48mhz (USB-CDC-ACM).
3
votes
3answers
4k views
How do I modulate PWM frequency in realtime with a Microchip dsPIC?
I'm trying to change the PWM output frequency roughly once a millisecond using a dsPIC33FJ256GP710, and I'm having mixed results. I first tried this:
...
2
votes
2answers
263 views
How to get higher frequency from DC power supply?
I desoldered a component, HY-05 Electro-magnetic sound generator, from a broken motherboard. Its DCV is 3~8V, operating frequency 2400 plus or minus 200 Hz. I can get a small metallic sound with the ...
5
votes
2answers
601 views
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 ...
3
votes
5answers
611 views
How to deal with a DC adapter with irregular voltage output?
Background information:
I tried hard to get a Schmitt-trigger working, but it kept failing. By accident I figured out, that my AC-to-DC adapter produces a very irregular voltage output (I could hear ...
9
votes
8answers
10k views
Maximum sample rate of Arduino Duemilanove?
G'day all!
I have an Arduino Duemilanove hanging around spare at the moment and thought I might try a few audio interfacing projects. I'm just wondering what sort of sampling frequency I can achieve ...
19
votes
6answers
3k views
How to convert AC to DC
I am designing a circuit that needs to output 5VDC @ 1A. I'm trying to use a wall transformer to step the voltage down to 12VAC. The next step is the diode bridge and ripple capacitor.
The ripple ...
4
votes
3answers
947 views
Audio Frequency Shift Keying to Arduino
I am attempting to have an Arduino interpret an AFSK signal, this is very vague but can anyone just point me in the right direction for detecting the frequency of the AFSK signal with an arduino?
4
votes
2answers
531 views
Relation between Power consumed and MCPS (million cycles per second) consumed on a processor
I have been working on a ARM cortex A8 board on mp3 decoder.
While doing this I have a requirement saying the mp3 decoder solution I am doing should consume 50mW. This generated few questions in my ...
