© Faraday Technology. As part of continual product improvement the specifications, details and dimensions shown in this publication are subject to change without notice

Fara163d

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Dec-99(A)

To avoid data errors the fast pulses produced by data generators need to be band limited prior to

insertion into a video channel.

When conventional low pass filters are used unacceptable time domain ringing of the pulse results.

This range of filters is designed to band limit while avoiding this problem.

Due to technical and historic reasons three types of filter are in current use. They are based on the

Gaussian, Raised Cosine and Cosine Roll-off realisations. Each has a slightly different

characteristic. The cosine roll-off type is the only one that band limits the frequency spectrum to

5.5 MHz so ensuring that a 625 line video system is transparent to the pulse.

FX055AD

FX055BD

FX055CD

Filter Type

Gaussian

Raised cosine

Cosine Roll-off

Attenuation at 5.5 MHz

3.0 dB

5.0 dB

19.0 dB

Impedance

75 ohms

75 ohms

75 ohms

Temperature Range

0°C to 70°C

0°C to 70°C

0°C to 70°C

Aqueous Washable

Yes

Yes

Yes

Package

DR00110A

DR00110A

DR00110A

TELETEXT FILTERS

A RANGE OF DIP PULSE SHAPING FILTERS

FOR TELETEXT SYSTEMS