Table 11-1.--Intensity Level and Audibility Range

The microfiche reader-printer is a self-

To ensure a wide variety of whistle characteristics,

contained machine designed for reading and

the fundamental frequency of a whistle must be

printing enlarged copies of microfiche images.

between the following defined limits:

There are normally two modes of operation:

reading and printing. During the reading mode, an

250 to 700 Hz, for a ship less than 75 meters

enlargement of the microfiche image appears on

(240 feet) long

the translucent viewing screen. A print of the

image may be made by pressing a PRINT button on

130 to 350 Hz, for a ship 75 to 200 meters

the console of the machine. After an exposure and

(240 to 650 feet) long

development cycle, the print emerges from a slot in

the cabinet.

70 to 200 Hz, for a ship more than 200

meters (650 feet) long

The

microfiche

reader-printer

consists

basically of six systems. These are the optical system,

INTENSITY

light source, paper feed system, developing system,

paper cutter, and power distribution system. These

A whistle shall provide in the direction of

systems are all housed in a cabinet and frame

maximum whistle intensity and at a distance of 1

assembly.

meter from the whistle, a sound pressure level in at

least one 1/3-octave band within the range of 180 to

OPTICAL AND LIGHT

700 Hz ( + 1 percent) as listed in table 11-1.

SYSTEMS

MAINTENANCE

The purpose of the optical system is to project

an image in sharp focus on the viewing screen. This

Maintenance

should

accomplished

is accomplished with a system of mirrors and lens.

according to the applicable technical manual. All

Figure 11-1 is an optical system from a 3-M 500

preventive maintenance should be accomplished

Reader-Printer. In this particular system, the

according to the preventive maintenance card for the

reflector is adjustable to allow concentration of the

system aboard the ship at the time.

light rays.

MICROFICHE EQUIPMENT

The lamp is the source of the light rays.

Normally, the voltage of the lamp is adjustable. This

There are many types and sizes of microfiche

allows the operator to select the proper exposure for

equipment in use today. Regardless of size and shape,

the particular microfiche image.

they all accomplish the same job.

Table 11-1.--Intensity Level and Audibility Range

11-2