鈰?/div>
Rx
The MX214/224 Variable Split Band Inverters are designed for mobile and cellular radio voice security
applications. Digital control functions are loaded serially into the MX214. The MX224 is loaded in parallel.
The MX214/224 ICs include a highpass filter that rejects subaudio frequencies, ensuring full CTCSS
compatibility. This CTCSS filter is not included on the earlier generation MX204 VSB Inverter.
The MX214/224 splits the voiceband (300-2700Hz) into upper and lower subbands, and inverts each subband
about itself. The 鈥榮plit point鈥?(defined as the frequency where the voice band is subdivided), is externally
programmable to 32 distinct values in the 300 to 3000Hz range. In the 鈥榝ixed code鈥?mode, a single point is
used. Fixed mode operation nets approximately 4 mutually exclusive secure channels.
In 鈥榬olling code鈥?mode, the split point is changed many times per second, usually under control of a
microprocessor. Rolling code scrambling requires synchronization, offers higher security than fixed code
operation, and provides a much greater number of mutually exclusive secure channels.
The MX214/224 offers a recovered audio product close to that of a telephone. The on-chip 鈥?Mute鈥?function is
useful when implementing rolling code continuous synchronization schemes. 鈥楶owersave鈥?and
鈥楥lear/Scramble鈥?controls are also included on-chip. Timing and filter clocks are derived internally from an
on-chip 1MHz reference oscillator driven by a 1MHz crystal or clock pulse input.
The MX214 and the MX224 operate from a single 5.0V supply and available in the following packges:
22-pin CDIP (MX214J/MX224J), 22-pin PDIP (MX214P/MX224P), and 24-pin PLCC (MX214LH/MX224LH).
1998
MX-COM, Inc.
www.mxcom.com Tel: 800 638 5577 336 744 5050 Fax: 336 744 5054
Doc. # 20480112.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
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