VideoPreservation Website

Chapter 11

Basic Videocassette Systems

Videocassette recording and playback systems represent a significant advance over 3/4-inch EIAJ systems. Since the tape remains in a sealed container and is threaded automatically in a videocassette system, the trouble-free life of the tape and the video unit is greatly extended. Videocassette machines are particularly ideal for playback and recording situations where a variety of untrained people must operate a video machine.

U-Matic 3/4inch Videocassette Recorders

The operational controls on a U-Matic 3/4-inch VCR (Videocassette Recorder) differ somewhat from one series of the same machine to another and also within the same manufacturer's models. Nevertheless, all videocassette machines must include additional controls such as PAUSE/STILL FRAME, RECORD, AUDIO DUB, and EDIT. Also,VCR plugs and connectors are basically identical to reel-to-reel VTRs. Earlier model Sony VCRs such as the VP-1200, VO-1600 and VO1800 utilized mechanical function buttons which required the operator to wait between modes to prevent the machine from jamming. The Sony Type II machines and most JVC VCRs feature feather-touch SOLENOID CONTROLS and LOCK-OUT LOGIC which nearly eliminate operator control error.

Special Features of Most Sony Type II and other sophisticated VCRs:

• LOGIC CONTROL SYSTEM—A LOCK OUT LOGIC feature prevents the activation of the "wrong button." Any button can be pressed at any time without going first to the STOP mode or damaging the tape or the machine. The logic control circuits remember which buttons have been pushed but permit only the correct sequence of machine operations to occur, thus eliminating any chance of operator-control error. Most of us could surely use one of these, couldn't we?

• IMPROVED PICTURE QUALITY and Signal-toNoise Ratio—Type I I VCRs have a 45 db signal-to-noise ratio vs. 40-42 db for EIAJ VTRs. An increase of 5 db represents a noticeable and significant increase in picture quality and purity. This improvement allows copies to be made with very little loss in quality.

•PAUSE CONTROL—The tape motion can be stopped or started in either recording or playback mode without dethreading the tape. This is an essential feature for cueing or editing.

• AUTO/MANUAL LIMITER for Audio Recording—This control allows the selection of automatic or manual modes for audio recording. When the limiter is on, high level peaks and distortion are reduced without altering the dynamic range of the sound. Older AGC (automatic gain control) circuits would boost low sounds and extraneous noise,causing undesirable audio elements to be recorded on the tape.

• FULL AUTOMATIC REWIND—When the tape stops at the end of the program, the machine rewinds it automatically.

•AUTOMATIC REPLAY/CONTINUOUS REPLAY—The machine rewinds and continuously replays the tape. This is very useful for sales demonstrations and informational situations.

•PROGRAMMABLE MEMORY—The VCR will automatically return to a preselected point in the tape.

• REMOTE CONTROL—Optional remote control devices allow computer or distant operator control of the machine's tape functions.