I understand using the pattern to find the output line single phase but how is the amplitude determined?
How is the amplitude of an output signal of a binary input determined using a constellation pattern?
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But how is the amplitude determined?
By the length of the line from the origin to each constellation point: -
The above image has equal amplitudes for all four binary values hence they sit on the circumference of a circle.
The one below has 8 binary values and the amplitude of the inner four is smaller than the outer four.
answered Jan 23, 2020 at 16:43
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\$\begingroup\$ Is this true as well for a binary signal? \$\endgroup\$ Commented Jan 23, 2020 at 16:48
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\$\begingroup\$ It usually is but needn’t be theoretically. BPSK (binary phase shift keying) is a good example of two points having equal amplitude but a phase angle of 180 degrees between the two signals. \$\endgroup\$– Andy akaCommented Jan 23, 2020 at 16:50
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\$\begingroup\$ So first image is 1v. 5v, 0v range second image would be 1v, 0.75v ,0.5v 0v range? \$\endgroup\$ Commented Jan 23, 2020 at 16:59
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\$\begingroup\$ I don’t know how you arrived at those numbers frankly. In the 1st diagram, all amplitudes are the same because all four binary vales are represented on one circle having a constant radius. \$\endgroup\$– Andy akaCommented Jan 23, 2020 at 17:04
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\$\begingroup\$ If you are wondering how each constellation point is ascribed a binary value then that is completely arbitrary. The example binary values in my pictures are purely examples and need not be like that. \$\endgroup\$– Andy akaCommented Jan 23, 2020 at 17:06