.- Island Labs

PRODUCT INFORMATION

Publication D/204/6 November 1986Provisional Issue

Features 'EI' Applicationso *Variable Split Band 0 Frequency Domain Speech0 300-3400Hz Bandwidth Scramblere Programmable Split Frequency 0 Fixed Code Scrambler0 Crystal Oscillator Stability 0 Rolling Code Scrambler0 Single CMOS Chip in 28-Lead o For Cellular Telephones

Package Mobile Radio0 Single 5 Volt Supply Cordless Telephones

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Brief DescriptionThe FX204 is a two-band frequency inversiondevice intended for use in speech scramblingapplications. The FX204 uses switchedcapacitor filters to split the voice spectruminto high and low frequency bands andbalanced modulators to invert each frequencyband about its own centre frequency. Thesplit point frequency is externallyprogrammable to 32 different points in therange 300 to 3000Hz and makes the FX204suitable for both fixed programmable and

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rolling code speech scramblers. All filtercut-off frequencies and inversion carriers arederived from a single reference crystaloscillator and facilities are provided to inputand output synchronisation tones whererequired. Constructed in a 5 volt singlesupply CMOS process and available in28-pin DIL and surface mount packages, theFX204 is suitable for use in fixed or portableequipment.

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