Exchange of information between devices. Communication can be wired or wireless.
1
vote
1answer
111 views
digital voice on gsm modules
I would like to understand how to handle digital voice on gsm modules.
After reading 3gpp gsm mux 07.10 specification it is my understanding that gsm modules can be configured to transport voice ...
0
votes
5answers
129 views
Good RS232-based Protocols for Embedded to Computer Communication
I'm working on a project that involves a good bit of data communication between a remote Arduino and a computer. The wireless connection is through a pair of XBees, so we have a RS232 link between the ...
3
votes
3answers
152 views
Why is probability theory that important to communication theory?
Since Shannon's paper Mathematical theory of communications, probability theory has played an important role on communications (digital and analog).
I've been checking some course descriptions on my ...
0
votes
0answers
40 views
Erlang B telecom system (grade of service)
I am bit stuck with an answered question that I found online:
We have an Erlang B system where the total number of served call is 15.48 erlangs. The system contains 23 circuits. The incoming calls ...
1
vote
3answers
660 views
How to create a multi-extension intercom system using wired phones?
I want to create a simple (telephone based) intercom system in our new house. Shouting between rooms is not so good, and trying to use an IM client or Facetime doesn't have the immediacy of a good ...
3
votes
2answers
99 views
How good is coaxial cable?
My question relates to the accumulated AC voltage that will appear on the screen of a length of coax:
If the cable is properly terminated at one end and fed with data (or any signal) at the other ...
0
votes
1answer
67 views
Calculating the model complexity for wireless sensors
I am coming from geoinformatic background and I do not know anything about the electrical issues.
I have a model for outlier detection for wireless sensor and I want to assess the energy complexity ...
2
votes
3answers
804 views
Starting with I2C on PIC18s
For a project I'd like three PICs (two slaves PIC18F4620, one master PIC18F46K22) to communicate over the I2C bus. Later on, more slaves may be added (like EEPROM, SRAM, ...). I'm writing the code for ...
3
votes
0answers
56 views
Faulty RS-485 device has irregular effect on neighboring devices in bus setup
I am trying to understand the mystery of how one faulty RS-485 transceiver, in a network bus with several devices, seems to have very irregular influence on its own and its neighbors transmission ...
0
votes
0answers
48 views
Multiplex data and LED pin
I'm looking at performing a chip conversion for the Sparkfun LED RingCoder. The sample code provided with the product works well on an Arduino UNO, but it uses a pin for each I/O - 5 pins for the ...
1
vote
1answer
99 views
FM Transmitter and transmission
This is an FM transmitter circuit found in Internet Link.
Before doing ,I'm simulating in multisim. Since there is no mic input,I have given sine wave generator
1).What is frequency of wave must ...
2
votes
2answers
630 views
Microchip PIC24F & Android device: Which can be host device?
I work on a project where I want to connect PIC24F (Accessory Development Kit for Android www.microchip.com/android) and Samsung Galaxy S2 that I updated from android 2.3.3 to android version 2.3.4.
I ...
2
votes
1answer
86 views
Selecting communication between microcontrollers at high temperature
I have been assigned to a project to find the best possible communication between several PCB boards which have microcontrollers for a specific function. I need to have all microcontrollers ...
4
votes
3answers
104 views
Phase locked Loop in Demodulation
Can someone please clarify how a PLL works and how it can the result is used to deduce phase?
My understanding is that a PLL is used to demodulate in situations when the demodulator knows the ...
-1
votes
0answers
44 views
Wake up a node wirelessly [closed]
I have an RF UART module device which is sleeping (master device). I can wake it via a timer and force it connect to any available slave-nodes and talk via RS232. However, I am wasting battery this ...
0
votes
1answer
52 views
why does signal attenuation caused by shadowing vary?
Given a RF sender and a receiver, suppose the obstacles between them are fixed, both their material and dielectric properties, does the signal attenuation caused by their shadowing vary over time? If ...
2
votes
0answers
45 views
why is shadow fading also called slow fading and large-scale fading?
I've encountered several similar claims regarding shadow fading on several books, and have some difficulty understanding them.
(1) Shadow fading is called slow fading because the duration of the fade ...
1
vote
1answer
76 views
i2c maximum bus speed calculation
This question is based on the Philips I2C specification UM10204.They gave (section 7.2.1, page 56) for calculating the maximum frequency of the bus:
...
-1
votes
0answers
38 views
Bus and short circut [closed]
I have a problem with some Ultra sonic heat meters and Mbus. As soon as I connect the bus to the level converter the level converter indicates short circuit. If I change the voltage supply to the ...
0
votes
2answers
85 views
Strange I2C behavior: sometime it works, some time it doesn't
I am using Arduino Ethernet with PoE and Arduino Uno boards. In recent days I implemented a working I2C bus by using the Wire library and all it seemed almost to ...
-3
votes
1answer
54 views
Best way to Interface with PC/MAC/iDevices/Smartphones [closed]
What do you think is the best way to communicate a hardware with PC, MACs, iDevices and Smartphones (with Android, Windows Mobile, etc.) ?
We need to make a voice chat (like VOIP) and also exchange ...
-3
votes
1answer
42 views
A uniform scalar quantizer
I have a uniform scalar quantizer with M=4 levels of quantization, and a natural mapping from levels to bits of the 01000110111110 Frame. Is it possible that this ...
0
votes
3answers
204 views
Serial communication in Atmega128
I want to send some string to PC via serial port. In cute com (software) its displaying the string but with some chars missing. Also some hex numbers are appended at the start and end of the string. ...
-2
votes
1answer
43 views
what are the things to keep in mind when interfacing two digital devices?
what are the things to keep in mind when interfacing two digital devices, e.g FPGA with a dual shock controller or CPLD with a PS/2 Mouse, Microcontroller with an FPGA, FPGA with an external RAM.
One ...
2
votes
2answers
59 views
Connecting two STM32f4discovery boards
We have two STM32F4Discovery boards with Micro USB's for serial communication.
Is it possible to connect two boards to allow communication between them?
Is there is any different hardware other than ...
1
vote
2answers
157 views
How to set RN171 module work on UDP?
How to set RN171 module work on UDP?
for i have look the user munual,but always failed.
Anyone knows how to set,pls give me some advices.
thanks.
5
votes
3answers
265 views
Ethernet connector and transformers
I'm working on an Ethernet connection for a PIC18F4620 with the ENC28J60. I found a useful article here, with a schematic:
I see I need transformers between the RJ45 connector and the Ethernet ...
11
votes
3answers
1k views
Why do people use AT commands in serial communication?
I need to know why people in embedded systems use AT commands?
When I have asked people say that it is a standard.
So my question is: What does "AT" means? Why do people keep saying it's a standard?
...
19
votes
9answers
5k views
Software to create timing diagrams
In my professional life, I sometimes need to create timing diagrams for UART/SPI/etc protocols. However, I cant find any good programs available. Do any of you recommend any programs for this that ...
-2
votes
1answer
48 views
Choosing a good 4+ pin connector/cable for connecting AVRs [closed]
I'm working on a project where I2C and power is passed between multiple devices and am trying to select a good choice of connector/cable to use between devices which will be daisy chained.
The key ...
6
votes
3answers
358 views
Information regarding DC wander
I was just going through a text book on digital communication where something related to ac coupling was mentioned.It was mentioned that if a long stream of one(1) is encountered at the receiving end ...
1
vote
1answer
26 views
Power delay profile and broadband bus
I came across the following solved question, but I have trouble understanding part of the solution. If anyone could shed some light into this I would be really grateful since this problem has been ...
2
votes
2answers
109 views
I2C pull-up resistors calculation & where to place them
I'm connecting a PIC18F46K22 (master) to a PIC18F4620 (slave) using I2C. The wire between the devices is ~30cm. I'm using 400kHz without slew rate control. Later on, I'll add another 18F4620 on ~5cm ...
-3
votes
2answers
93 views
Free space model (wireless communications)
The received power at a given distance = 1km is 1nW .
Find the received power at a distance of 5km from the same transmitter , using the Free Space Model.
Suppose that frequency is 1800Mhz, ...
1
vote
4answers
164 views
What is the Need for modulation
What is the need for any kind of modulation in order to transmit signals?
4
votes
0answers
99 views
Help to identify unknown Sync Serial Bus
Does somebody already seen a sync serial bus communication like that ?
Repeated Pattern :
Detail of beginning :
I fail to identify it...
it look like I2C but :
it have a clock at 2MHz (so ...
2
votes
2answers
67 views
Realizing an flexible, but fault tolerant, infrared communication chain
The task fell on me to realize a wireless, daisy chained communication system. The communication must be wireless, esp. via infrared diodes. The end of the chain is connected to a PC (wired).
The ...
9
votes
6answers
3k views
Wireless communication between more than two Microchip PIC microcontrollers
I would like to create wireless communication between Microchip PICs for my simple project.
It's actually an one way communication but there is one server and more than one client (about 2-4, all ...
0
votes
2answers
110 views
Checksum done without microcontroller
How could I transmit data from a device such as a distance sensor or quadrature encoder with an RF transmitter and also transmit a checksum or will I have to use a microcontroller such as the Arduino?
...
3
votes
2answers
90 views
UHF Phase Modulation
I would like to design a system that produces -10 degrees and +10 degrees phase shifts at 409.6MHz (Basically BPSK).
The way I'm thinking about approaching this is by using a DDS to generate the BPSK ...
2
votes
2answers
119 views
I2C: Is a repeated start between different slave addresses legal?
I'm writing I²C code for an application where I have only one master, but several slaves. In all the datasheets I've read (not only for this project), the repeated start condition is only used to ...
-3
votes
2answers
70 views
Would we have communication theory and systems without trignometric ratio? [closed]
Trigonometric identities happen to be invented for triangles: sin, cosine and through them tangent.
Later at school I learnt that they are periodic and have wave appearance. Than in University I came ...
1
vote
2answers
142 views
Calculating maximum data rates
A channel has bandwidth 3 KHz, signal to noise ratio is 40 dB find maximum data rate for 16 level encoding schemes.
There are two ways to find channel capacity. First one is with Nyquist theorem and ...
1
vote
1answer
140 views
Embedded system engineer's guide to GUI [closed]
For an engineer who solely knows C/C++ for programming microcontrollers, and has no idea about developing fancy GUI application for communication with his embedded systems, Which book and IDE might be ...
0
votes
1answer
211 views
STM32 - PC serial sommunication
What are the available options or ways to connect the STM32 discovery board using UART to a PC via USB or the serial port ? What is the required hardware/cables ?
2
votes
1answer
145 views
FM Quadrature detector - is it the best choice
My input is an FM carrier of 80.00MHz. It is FM modulated with 625kbpsec data. The deviation from carrier is about +/-700kHz. The data never spends more than about 38us in a low state or high state ...
3
votes
2answers
128 views
Is it OK to have data lines and AC in the same multicore cable?
I need to provide the following over sections of 1m multicore cable, totaling around 15m.
240v AC
5v DC
GND
RX
TX
Will the AC cause problems for the Serial data?
2
votes
3answers
76 views
Connecting a simple device with my secured home wifi
I am planning on building a simple device, which retrieves information over wifi. The device shall be as cheap and simple as possible, so it won't have a keyboard or a display.
My question is: What ...
4
votes
1answer
332 views
Digital IQ Modulation [closed]
I have been looking into IQ-modulation and found myself a little confused.
"Traditionally" IQ-Modulation schemes goes something like this:
IQ_Data -> 2 x DAC -> IQ_Modulator -> RF
But I have seen ...
3
votes
2answers
56 views
Rationale for interleaving in G.709
According to the ITU-T G.709 (OTN) specification, a single frame has 4 'rows' and 4080 'columns' of octets, arranged like this:
...
