Internal Functions - Canon 4K501ST Manual

3-5 Internal functions

● HDCP
This product is an HDCP version 2.2/1.4-compliant image device.
The digital image signals for HDCP contents that are encrypted and sent from digital devices connected
to the HDMI terminal and DVI terminal can be displayed.
HDCP is an "encryption system for digital video signals."
It AISYS a TMDS link with DVI or HDMI terminals.
HDCP transmitter is built in the signal server and HDCP receiver is built in the signal receiver.
This system can make the signals code, transmit, decode and display.
1. The transmitter authenticates the receiver: If the authentication fails, signals are not transmitted.
Immediately after authentication, a key (the encryption rule) is shared: The key is updated every two
seconds.
2. The transmitter encrypts the information with the key and sends the encrypted (digital) signal. If the
key update does not match, the transmissions stop.
3. The receiver receives the encrypted signal, decodes the signal with the key, and displays the signal on
the display device.
● Frame lock function
Depending on the input signal's frequency, commonly-used display devices may not be able to synchronize
the input signal's frame with LCD's frame, thereby showing a mixture of successive 2 frames.
The following illustrates how this mixture of frames (image shift) occurs. Numbers ① to ③ indicates the
order in which these images appeared.
①
In this example, a composite image ② appeared when an object moved from right to left, which is a
combination of the frames before and after the movement.
This function synchronizes the LCD's frame with that of input signal to prevent this kind of frame mixture,
and it is effective for input signals of about 23 to 31 Hz and about 47 to 61 Hz.
For frequencies other than these ranges, a different process takes effect in place of Frame Lock
(synchronization) to ensure that a single frame appears in the entire LCD. Therefore, composite image like
② would not appear even in those cases.
In the past, asynchronous methods were adequate for inputs from computers because they mainly
consisted of still images so no image overlapping could be seen. When moving images are played back,
however, image-overlapping takes place because of a slight difference between the image signal and the
LCOS-panel drive frequency. As more moving images are played back from computers these days, the
frame lock function is used to synchronize computer inputs to counteract this problem, resulting in
smooth image playback.
(14/22)
② ③