Lectrosonics VS1 User Manual

VS1

VIDEO SWITCHER INTERFACE

OPERATING INSTRUCTIONS

and trouble-shooting guide

LECTROSONICS, INC.

Rio Rancho, NM

INTRODUCTION

The VS1 Video Switcher Interface is a microprocessor-based controller used between an automatic microphone
mixer and a video switcher. The VS1 provides sophisticated capabilities to synchronize video recording (with up to
8 video cameras) to the audio being recorded, using the logic output capability of an automatic mixer. Typical
applications for the VS1 are in audio/video teleconferencing, courtroom video recording, and security applications.

The VS1 is fully programmable from front panel controls, and may be quickly and simply set up for optimum
performance in a variety of applications. Input and output connections are standard screw type terminal strips for
ease of installation. The Auto-Sync capability of the VS1 allows camera switching during the vertical retrace
interval for video systems which are synchronized to an external timebase. This eliminates any rolling or other
video anomalies as different cameras are activated.

TABLE OF CONTENTS

INTRODUCTION .......................................... 2

THEORY OF OPERATION ................................... 3

VS1 FUNCTIONS .......................................... 4

VS1 Function Summary and Default Settings ...................... 5

FRONT PANEL DESCRIPTION ................................ 6

REAR PANEL DESCRIPTION ................................. 6

INSTALLATION ........................................... 7

SETUP PROCEDURE ....................................... 8

TROUBLESHOOTING ....................................... 10

SPECIFICATIONS ......................................... 10

SERVICE AND REPAIR ..................................... 11

RETURNING UNITS FOR REPAIR ............................. 11

WARRANTY ........................................ Back cover

VS1MAN 0993

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THEORY OF OPERATION

The general operation of the VS1 will be described in this section, while the specifics of each programmable option
will be outlined in the Operating Instructions.

A Motorola MC68HC705 microcontroller is the heart of the VS1. The MC68HC705 controls both the switching
relationships between the logic inputs and logic outputs, as well as all user interface functions. Since the
MC68HC705 is so highly integrated, parts count is kept to a minimum in the VS1, resulting in higher reliability.

The VS1 provides intelligent connection of an automatic mixer to a video switcher by interpreting the microphone
activity and keying the appropriate camera. A programmable Input Time Delay allows a user selectable waiting
period after microphone activity commences before the camera associated with that microphone is activated. This
prevents unwanted camera switching caused by coughs, paper rustling, and other transient non-speech sounds. A
programmable Hold Time Delay allows a user selectable waiting period when microphone activity stops before
moving to another camera. This hold time is used to cover pauses in speech, again avoiding unwanted camera
switching. When no microphones are active, the VS1 may be programmed either to hold the last active camera or
switch to an overview camera. When multiple microphones are simultaneously active, the VS1 may be
programmed to rotate between all active microphones, switch to the overview channel, or key two cameras (for
video switchers with split screen capability).

Figure 1 - VS1 Block Diagram

An override capability is provided if one or more outputs need to take precedence over other outputs. Any
output(s) may be set as an override output. When an override output becomes active, no other outputs are allowed
to become active until the override output is no longer active. Override capability is useful if a camera needs to be
forced on, irrespective of microphone activity. A switch may be connected to the logic input of an override output to
provide a means to "force on" that output.

Besides the normal mode of operation, two other operational modes are provided on the VS1: Scan mode and
Manual mode. The Scan mode continuously rotates through all eight outputs, activating them each individually.
The Manual mode allows any or all outputs to be activated or deactivated manually from the front panel.

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VS1 FUNCTIONS

Input Time Delay - Input Time Delay may be adjusted between 0.1 and 10 seconds. This parameter represents

the delay between activity on any VS1 logic input and the activation of the associated logic output. The Input Time
Delay is factory preset for 2 seconds, but may be adjusted as appropriate to insure that inadvertent camera
switching does not take place from transient sounds such as coughs, paper rustling, and the like. See the Logic
Input/Output Timing Diagram below for further explanation of Input Time Delay.

Hold Time Delay - Hold Time Delay may be adjusted between 0.1 and 25 seconds. This parameter represents the
delay between the cessation of activity on any VS1 logic input and the deactivation of the associated logic output.
The Hold Time Delay is factory preset for 7 seconds, but may be adjusted as appropriate to insure that inadvertent
camera switching does not take place from normal pauses in speech. See the Logic Input/Output Timing Diagram
below for further explanation of Input Time Delay.

Idle Option - Idle Option determines the operation of the VS1 when no logic inputs are active. There are two
choices: Hold and Overview. The Idle Option is factory preset for Hold. Hold simply leaves on the last active
channel. Overview switches to whichever camera has been programmed to be the overview camera (see Overview
Output description).

Simultaneous Input - Simultaneous Input determines the operation of the VS1 when multiple logic inputs are
active. There are three choices: Rotate, Multiple, and Overview. The Simultaneous Input option is factory preset
for Rotate. Rotate continuously selects each active input singly, and holds on that camera for a time period
determined by the Rotate Time parameter (see Rotate Time). Multiple allows the VS1 to activate up to two
cameras when multiple logic inputs are active. The first two active logic inputs are selected. The Multiple option
accommodates video switchers with split screen capability. Overview simply switches to the programmed overview
camera (see Overview Output description) when multiple cameras are active.

Rotate Time - Rotate Time may be adjusted between 0.1 and 10 seconds. The Rotate Time represents the length
of time each camera remains on if the Rotate option is selected for Simultaneous Input operation. Rotate Time is
factory preset for 1 second. Note that the Rotate Time parameter is also used in the Output Scan Mode to
determine the scan rate.

Overview Output - Overview Output determines which of the eight cameras is the overview camera. The overview
output is factory preset to output 1.

Output Mode - Output Mode determines whether the logic output is Continuous or Pulsed. The Output Mode is
factory preset to Pulse, but may be reset according to the requirements of the video switcher.

Override Output - Any single output (or any combination of outputs) may be assigned as Override Outputs. When
an Override Output is active, no other outputs can become active until the Override Output is no longer active. The
factory preset is no outputs assigned as Override Outputs.

Auto Sync - Auto Sync determines whether the VS1 will switch outputs during the vertical retrace interval of gen­locked systems or not. With Auto Sync "On", the VS1 will synchronize output switching to the vertical retrace
interval if a suitable synchronization signal is available at the 75 Ohm Sync Input. If there is no sync signal but
Auto Sync is "On", output switching will not be synchronized with the vertical retrace interval. If Auto Sync is "Off",
the VS1 will not synchronize output switching regardless of the presence or absence of a sync signal.

Output Scan Mode - Output Scan Mode activates each output consecutively, regardless of the activity on the logic
inputs. The amount of time each output is active is equal to the setting of the Rotate Time parameter.

Manual Mode - Manual Mode allows each output (or any combination of outputs) to be activated or deactivated
manually, via the front panel controls.

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