[mythtv-users] What FCC ruling requires OTA digital unencrypted?

[Derek Meek]

Craig Partin wrote:

>>Maybe it's QAM256 and the TV only does QAM16?
>>    
>>
>
>I used the QAM256 channels file.  It's possible they use different
>modulation methods in different areas but improbable.  I think the QAM
>tuners are fussy in general.
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>
QAM256 is not very tolerant of line noise
/
By moving to a higher-order constellation, it is possible to transmit
more bits <http://en.wikipedia.org/wiki/Bit> per symbol
<http://en.wikipedia.org/wiki/Symbol_%28data%29>. However, if the mean
energy of the constellation is to remain the same (by way of making a
fair comparison), the points must be closer together and are thus more
susceptible to noise <http://en.wikipedia.org/wiki/Noise> and other
corruption; this results in a higher bit error rate
<http://en.wikipedia.org/wiki/Bit_error_rate> and so higher-order QAM
can deliver more data less reliably than lower-order QAM.
/
http://en.wikipedia.org/wiki/Quadrature_amplitude_modulation/
/