Panasonic SC-HT790V - Manual (Page 59)

59
RQT6951
Glossary
Decoder
A decoder restores the coded audio signals on DVDs to normal. This
is called decoding.
Dolby Digital
This is a method of coding digital signals developed by Dolby
Laboratories. Apart from stereo (2-channel) audio, these signals can
also be multi-channel audio. A large amount of audio information
can be recorded on one disc using this method.
Dolby Pro Logic
A surround system where a 4-channel audio track is recorded as
2 channels and then is restored to 4 channels for play. The surround
channel is monaural and can reproduce up to 7 kHz.
DTS (Digital Theater Systems)
This surround system is used in many movie theaters around the
world. There is good separation between the channels, so realistic
sound effects are possible.
Dynamic range
Dynamic range is the difference between the lowest level of sound
that can be heard above the noise of the equipment and the highest
level of sound before distortion occurs.
Film and video
DVD-Videos are recorded using either film or video. Usually, film is
recorded at 24 frames per second, the rate movies are filmed at,
while video is recorded at 30 frames per second.
Frame still and field still
Frames are the still pictures that make moving pictures. About thirty
are shown each second. A frame still may appear blurred but overall
quality is high.
Two fields appear alternately to make up one frame. A field still is
not blurred but picture quality is lower.
Interlace and progressive output
NTSC, the video signal standard, has 480 interlaced (I) scan lines,
whereas progressive scanning uses twice the number of scan lines.
This is called 480P.
I/P/B
MPEG 2, the video compression standard adopted for use with
DVD-Video, codes frames using these 3 picture types.
I: Intra coded picture
This picture has the best quality and is the best to use when
adjusting the picture.
P: Predictive coded picture
This picture is calculated based on past I or P-pictures.
B: Bidirectionally-predictive coded picture
This picture is calculated by comparing past and future I and
P-pictures so it has the lowest volume of information.
Linear PCM (pulse code modulation)
These are uncompressed digital signals, similar to those found on
CDs.
To clean this unit, wipe with a soft, dry cloth.
≥Never use alcohol, paint thinner or benzine to clean this unit.
≥Before using chemically treated cloth, read the instructions that
came with the cloth carefully.
Cleaning the video heads
Dirt on the video heads can cause poor recording and play.
To clean the heads, insert and eject a tape 5 to 10 times in
succession.
If the picture does not improve, use an optional head-cleaning
cassette (part number NV-TCL30PT). If the problem persists, seek
advice from a qualified service person.
Maintenance