A method of operating a light source (100) including a ballast (110) in
electrical communication with a lamp (120). The method includes operating
the ballast (110) to determine (920) an average lamp power to be applied
to the lamp (120) during a data period. The method further includes
operating the ballast (110) to generate and communicate (930) a pulse
width modulated drive signal to the lamp (120) during the data period,
the pulse width modulated drive signal having one of a first waveform and
a second waveform for applying the average lamp power to the lamp (120),
the first waveform including at least one pulse representative of a first
data bit, the second waveform including at least one pulse representative
of a second data bit. The method additionally includes operating the lamp
(120) to emit (940) a modulated light output in response to a reception
of the pulse width modulated drive signal during the data period, the
modulated light output being representative of the first data bit in
response to the pulse width modulated drive signal having the first
waveform, the modulated light output being representative of the second
data bit in response to the pulse width modulated drive signal having the
second waveform.