For each channel, call ChannelAvailable. If this method returns false, do not
display the channel to the user. If this method returns true, it
will have found the exact frequency for the channel.
If ChannelAvailable is finding too many channels with just noise then
check the SignalPresent property after calling ChannelAvailable.
If SignalPresent is true, then the channel is most likely a valid, viewable
channel. However this risks missing viewable channels with moderate noise.
See SignalPresent for more information on locking on to
a channel.
It is no longer required to perform a scan for each chanel's exact
frequency. The tuner automatically finds the exact frequency each
time the channel is changed.
This method correctly uses frequency-overrides. As described in
the DirectX SDK topic "Collecting Fine-Tuning Information", this method
does not use the IAMTVTuner.AutoTune() method. Instead it uses the
suggested put_Channel() method.