數位電視也會有訊號不好的問題嗎？
Yes.
不然那來的 Signal Quality(訊號品質), Signal Strength(訊號強度) 指示燈 (WinFast DTV 有7個小藍燈, 幾個小藍燈是亮?)?
http://www.tvrobbs.com/showthread.php?threadid=4091
http://www.tvrobbs.com/showthread.php?threadid=4186
http://www.tvrobbs.com/forumdisplay.php?forumid=3
http://www.tvrobbs.com/showthread.php?threadid=4078
Source :
http://www.dba.org.au/index.asp?sectionID=25
Frequently Asked Questions about Installing Antennas for Digital Television Reception
Q:What is the Digital Cliff, or Threshold?
A:With analog television, as the signal strength is reduced, so the pictures steadily become noisier. With digital transmission, the quality of the pictures remains unaffected until quite suddenly the pictures fail altogether. This point is known as the Digital Cliff, or Threshold.
It's clearly very important to make sure that a receiver is normally operating well above the Threshold, so that variations in signal level (due for example to the antenna moving in the wind, or due to foliage growing on trees between the antenna and the transmitter) don't tip the signal over the Cliff.
Q:What is the 'operating window' of a receiver?
A:Two main factors limit the range of signal levels that should be present at the input to a DTT receiver. The first is the minimum level of the digital signal, which must not fall below the threshold (typically 35-40dB猩, but in some cases higher). The second is the maximum level of signal that can be applied before the receiver overloads. The highest signal is usually an analog signal, and this should not exceed 77dB猩.
All digital AND analog signals at the input to a digital receiver must fall within this 'operating window'.
Q:I've heard that it is important to measure signal levels, even in simple domestic installations. Why is this?
A:Simply to ensure that all signal levels are within the operating window of the receiver. Signal levels that are too high can impair or prevent reception. Signal levels that are too low can sometimes go over the Digital Cliff. For a reliable installation, both of these conditions must be avoided. Generally, installers who check signal levels have far fewer return visits.