Panasonic SCHT810V SAHT790V User Guide - Page 59

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. Maintenance 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. RQT6951 59