Pvt SQUELCH™ CTCSS Encoder/Decoder

The MX375 is a CMOS LSI microcircuit which combines CTCSS Encode/Decode operation with voice band frequency inversion. Frequency inversion is achieved by modulating the input audio with a 3333 Hz carrier frequency. Higher voice band frequencies are translated downward, and lower frequencies upward, resulting in a “mirror image” voice transmission. PvtSQUELCHcombines CTCSS with inverted speech to prevent users from understanding each other’s communications unless the transmissions are accompanied by the group’s assigned tone. Its net effect is to eliminate casual eavesdropping and give mobile radio users a certain degree of privacy at a minimal price. Up to 38 PvtSQUELCH user groups (one per CTCSS tone) can share a single radio channel. With PvtSQUELCH, competing businesses can share a radio channel without compromising communications security.

FEATUREs
• PRIVATE/CLEAR CAPABILITY
• ON-CHIP TX AUDIO PRE/DEEMPHASIS
• ALTERNATIVE TO STANDARD CTCSS “PARTY LINE”
• POWERSAVE OPTION

APPLICATIONs
• MOBILE RADIOS
• COMMUNITY REPEATERS
• TELEPHONE/RADIO INTERCONNECT SYSTEMS