BPSK, QPSK, 8PSK and QAM Calculator

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A little tool for various calculations revolving around PSK and QAM modulation types commonly found in ENG, SNG, and BAS applications. While most calculator on the web are tied to a particular operation mode like satellite or microwave, this tiny tool is very flexible and accommodates various input options for pretty much any mode of operation. This calculator is also extremely useful for amateur radio operators wishing to deploy digital modulation schemes.

Information Rate (Mbit/s)
Modulation
FEC-Rate
Reed-Solomon FEC
Guard
Roll-off
Data Rate (Mbps)
Symbol Rate (Msym/s)
3 dB Bandwith (MHz)
Occupied Bandwith (MHz)
Allocated Bandwith (MHz)
CAVEAT: Please note that this calculator is calculating the Nyquist bandwidth. The Nyquist bandwidth is the minimum bandwidth than can be used to represent a signal. This is the correct bandwidth for transmitters which deploy a Nyquist bandwidth filter, which is the case for most professional transmitters.

If not filtered, the main lobe will have a bandwidth of twice the Nyquist bandwidth. For instance, a BPSK signal with an information rate of 1 Mbps will have a Nyquist bandwidth of 1 MHz. If unfiltered, the bandwidth of the main lobe is twice the Nyquist bandwidth or twice the symbol rate. In the case of a BPSK signal with an information rate of 1 Mbps this would be 2 MHz.

For a given bandwidth (B), the highest theoretical symbol rate (fsym) is 2B.

fsym = 2B

4 thoughts on “BPSK, QPSK, 8PSK and QAM Calculator”

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  3. Very useful calculator. I was trying to get Mbps from number of Msym/sec at 256QAM on my cable modem, which this tool doesn’t support, but that’s okay. It helped me understand enough that I could figure it out on my own. Thanks!

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