The 7443 series are passive bandpass filters which have been designed for safety

critical applications. They are used in signalling, monitoring and supervisory sys-

tems where the information is carried by signals, typically in the audio frequency

band. The filters are designed to operate over the range of temperature experi-

enced in a non air-conditioned, unheated vehicle exposed to the temperature

extremes found anywhere in North America.

• The safety critical design feature provides that the output signal level falls

by at least 18 dB below normal if any internal component becomes shorted

or opens.

• The filters are mounted in hermetically sealed steel cans. These provide a

long life under adverse environmental conditions including high relative

humidity.

• The temperature stability is maximized by prolonged temperature cycling, prior to tuning, to reduce the disaccommodation factor

of the ferrite core materials. In addition, capacitors are selected whose temperature coefficient of capacitance is the inverse of the

temperature coefficient of inductance of the coils or transformers.

• All filters tolerate 350 volts peak-to-peak at frequencies outside the pass band.

• The filters are fitted with an octal plug to make the input and output connections. The filters have four 8-32 studs to provide

secure mounting and withstand vibration.

FILTER

Passive Audio bandpass Filter

7443 Series

An ISO 9001 Registered Company

229 Colonnade Road, Ottawa, Ontario, Canada K2E 7K3

ELECTRICAL SPECIFICATIONS @ 25˚C

Center frequency range:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .250 Hz to 10 kHz

Bandwidth: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .± 30 Hz to ± 250 Hz

Input level range: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .0.1 V to 3.5 Vrms

Input Impedance:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .200

Ω

Output Impedance:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2500

Ω

Steepness factor: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 - 15

Steepness factor is defined as:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bandwidth at 60 dB

Bandwidth at 3 dB

Voltage Insulation: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .750 VDC from input terminals to output terminals

Operating temperature:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-20°C to +50°C

Storage temperature:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to + 80°C

Note: Other frequencies, bandwidths, impedances and other characteristics are available upon request.