Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [qam]

The tag has no usage guidance.

0
votes
0answers
29 views

Choosing the right IC for modeling data over a GSM network [closed]

I want to send digital information over the GSM network (over the voice channel). For this purpose, I need a modem that can handle: Ultra narrow band (400HZ - 3400HZ). noise (There is a lot of noise ...
2
votes
1answer
45 views

Quadrature modulation Digital to Analog

I want to use an FPGA to generate quadrature modulated signals for use with an RF transceiver (something like MAX2828 ). I am confused specifically about how the digital to analog modulation should ...
0
votes
2answers
433 views

QAM signal equation

I have seen that QAM signal equation is written as sum or substraction between in-phase and quadrature component. Does it really matters if we write QAM signal equation with + or - sign? It depends ...
2
votes
1answer
258 views

QAM and constellation diagram

Based on this QAM 32 constellation diagram, how it is possible to have the sam values on I and Q axes for different combinations of bits, e.g. 000 and 011 or 000 and 101, as well as other two bits, e....
1
vote
2answers
300 views

what relationships exists between the BER vs SNR graphs of QPSK and QAM modulation schemes on data throughput. which scheme does better?

Using QAM and QPSK modulation schemes, RF field measurements like received signal power and pathloss were obtained from where the SNR values were estimated. Their BER values were also calculated and ...
1
vote
2answers
109 views

How is phase recovered from wireless signals?

I've wondered for a long time how phase information is captured for wireless signals. It's used in applications like QAM for decoding symbols and radar beam forming to to locate targets, but I've ...
0
votes
2answers
244 views

Why it was not possible to use 256-QAM in the past

What is behind the progress of speed in digital communications? For example going from analog modems to high-speed DSL/DOCSIS on the same old metalic lines... Why wasn't for example 256-QAM possible ...
1
vote
0answers
97 views

Showing QAM constellation diagramm on signal analyzer

I've been playing with some lab equipment recently in order to learn more about digital modulation techniques. I've connected R&S signal generator SMIQ 03B with the R&S spectrum analyzer FSIQ ...
1
vote
2answers
42 views

Do we take significance of bit into account while calculating bit error rate?

The question is broadly about bit error rate, but to be concrete, I am asking it in context of 16-QAM. Consider we have a rectangular 16-QAM modulation and also assume that we have grey coding. As I ...
1
vote
0answers
301 views

How to make QAM (quadrature amplitude modulation) of a square or sinc wave signal?

I found this discussion of QAM in a communications text book and internet. "...load it into Matlab using imread(), which will give you an array of ...
0
votes
0answers
306 views

QAM Modulation Frequency vs Carrier Frequency

In QAM (Quadrature Amplitude Modulation) theory what is the relationship between the modulation frequency and the carrier frequency called? It is often stated in QAM tutorials that the carrier ...