# Questions tagged [qpsk]

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### What does division order mean in Rayleigh Fading?

So I'm just beginning to understand how Rayleigh Fading works and I'm trying to model some different modulation schemes with Rayleigh fading channels. I'm doing this on MATLAB where one of the ...
20 views

### What is the difference between using a baseband representation of a QPSK modulation scheme and a theoretically simulated QPSK modulation scheme?

I'm looking to compare the BER vs SNR performance of a QPSK modulation scheme, one which is a theoretical simulation on MATLAB and the other is a baseband simulation on MATLAB but I'm struggling to ...
79 views

### Is there a method to get the carrier from the recieved QPSK signal?

If we have given a signal and we know that is a modulated QPSK signal, can we recover the carrier if we know the carrier frequency fc. Edit: A clarification, I do not have to do it in hardware, a ...
72 views

### Can we band pass filter QPSK signal?

Consider we have QPSK signal with carrier frequency 10kHz. Generally, we demodulate or use matched filter on the the QPSK signal and recover the transmitted bit or the symbols. If the QPSk signal is ...
42 views

### What is the minimum sampling rate for QPSK or what is the bandwidth of QPSK signal?

Consider we have created a QPSK signal with a carrier frequency 100kHz. Before applying matched filter or demodulation we need to take sampls from the received signal. So what is the minimum sampling ...
19 views

### Need some help in bit error rate calculation for QPSK when using Gray coding

Why is Probability of Bit Error = 2 times the Probability of Symbol Error in QPSK with Gray Coding. Is it because one bit error has the potential to cause two symbol errors (2 symbols where they ...
57 views

### Peak-to-Average Power Ratio in OFDMA Communication

I am looking for a formula to calculate the Average Power of a square wave used in APSK Modulation. In my textbook, the example above is given with no formula so I am a loss how the value for ...
84 views

### Offset QPSK Frame sync markers

What actual protocols exist out there that employ Offset Quadrature Phase-Shift Keying (OQPSK)? What do they use for the frame synchronization marker (or "preamble" or "sync word" or "flag")? Do ...
314 views

### How to interpret transitions in a QPSK constellation diagram?

I have one doubt regarding how to analyze a constellation diagram. It is from a QPSK transmitter. The constellation diagram looks typically as books (as a square as you can see in Figure 1), but for ...
81 views

The communications channel between a QPSK transmitter and receiver can introduce an arbitrary phase change. For this reason, differential QPSK is used. Differential QPSK seeks to solve the phase ...
394 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 ...
227 views

### Phase rotation for QPSK

I have two SDRs and I want to do a simple test: I want to send data values using QPSK modulation with coordinates: (1,1), (-1, 1), (1, -1), (-1, -1), but on Rx site I got all possible values on the ...
1k views

### Differentiating between 32-QAM and 32-PSK

A communication channel with 4 kHz bandwidth requires 40 kbps data rate. What is the most suitable modulation technique to use in this particular scenario? for this I used the Nyquist theorem. C=2B ...