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Download Communications IC Selection Guide
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Features RF The FX214 and FX224 are low-power CMOS LSI devices designed as Variable Splitband (VSB) Voice Scramblers. Variable Split-band (VSB) Frequency Inversion Voice Scrambler Thirty-two Programmable Split-point Frequencies CTCSS High-pass Filter High Recovered Audio Quality Half-duplex Switching Serial and Parallel Load Options: FX214: Serial FX224: Parallel Supply Requirement Range: 4.5 to 5.5 V Each device uses separate Rx and Tx paths which are switched for half-duplex operation. To prevent interference from sub-audio products, an on-chip Continuous Tone Controlled Squelch System (CTCSS) highpass filter is automatically switched to the input in Rx and to the output in Tx. Scrambling is achieved by splitting the input voice frequencies into upper and lower frequency bands using switched capacitor filters, modulating each band with selected carrier frequencies to ‘frequency invert’ the bands and then summing the output. A total of 32 different split-point and carrier frequency combinations are externally programmable using a 5-bit code; this code can be either fixed or varying (rolling) for greater security. ‘Sync/Speech Mute’, ‘Powersave’, ‘Clear’ and ‘Audio-Bypass’ facilities are controlled via external commands. Timing and filter clocks are derived internally from an on-chip oscillator requiring only a single external 1MHz Xtal or clock pulse input. This device demonstrates high baseband and carrier frequency rejection with good ‘recovered audio’ quality. Applications Mobile and Cellular Radio Fixed and Rolling Code Speech Scramblers Analogue Two-way Radio FX214 Variable Split-band Audio Scrambler FX224 VSB Scrambling with High Recovered Audio Quality Wireless Data Analogue Two-way Radio Products These ICs are available in serial or parallel command-loading functions: AROUND (PS)/THROUGH XTAL/CLOCK LOAD/LATCH SERIAL CLOCK 1MHz OSC. INPUT LATCHES XTAL ENABLE/MUTE CLEAR/SCRAMBLE EN\ MUTE CLEAR/ SCRAMBLE Rx/Tx (SER/PAR) Rx/Tx 1MHZ A0 VDD A1 A2 CLOCK DIVIDER ROM A3 CLOCK DIVIDER Packages FX214LG (L1) 24-pin PLCC FX214L2 24-pin PLCC FX224LG (L1) 24-pin PLCC FX224LS (L2) 24-pin PLCC Operating Temperature -40 to +85 ºC Digital Voice Marine Safety and Comms FX214: Serial FX224: Parallel. VBIAS VSS Ck8 CkA FC1 FC2 (SERIAL DATA IN) PS CLOCK SWITCHING Ck3 Ck3 EN PS Ck4 Custom A4 Rx/Tx Ck4 Rx EN PS Rx Tx Rx IN Tx OUT CTCSS Rx MUTE BIAS Rx PS +EN Tx BIAS Ck3 FILTER 3 FC2 BIAS Tx C5 FILTER 4 PS SCRAMBLE Ck4 MUTE Rx Rx OUT Embedded PS Tx PS Ck4 FC1 Tx PS Rx Tx Rx Tx PS BIAS BIAS CLEAR Tx IN FILTER 1 BIAS Tx CkA FILTER 2 PS +EN Rx BIAS Rx CkA C6 Brief FX214 AND FX224 Technical Basics min - typ 8.0 1.2 max - mA mA 0 300 to 3400 dB Hz 0 400 to 2700 300 to 3400 300 - dB Hz Hz Hz - Wireline Data and Telephony Typical Supply Current at 5.0V Powersaved Passband Characteristics Clear Mode Gain Frequency Range Scramble/Descramble Rx Gain Rx Frequency Range (-3dB) Tx Frequency Range (-3dB) CTCSS -3dB Point 31
