CMX808AP4 View Datasheet(PDF) - MX-COM Inc
Part Name
Description
MFG CO.
'CMX808AP4' PDF : 22 Pages View PDF
Family Radio Service CTCSS Processor
15
CMX808A Preliminary Information
5 Application Notes
5.1 General
The CMX808A is intended for use in radio systems where subaudio tone signaling is required for functions
such as Family Radio Service (FRS) Hand-helds, Amateur Radio Equipment, General Mobile Radio Service
(GMRS) and Short Range Business Radio.
The facility to decode any one of 7 programmed tones (or one-of-any if tone sets are dynamically
reconfigured) allows designers to offer attractive end features to:
• Simultaneously support multiple calling tone codes e.g. children, parents and family with unique paging
and/or visual alerts used to identify each calling party or group.
• Effectively scan and 'learn' received tones to make Rx tone configuration easy and nearly automatic.
Configurable decoder bandwidths provide the flexibility to optimize performance under different operating
conditions such as when congestion or long distances alter signal quality.
5.2 Transmitter
The transmitter is enabled with Bit 7 in the SUB-AUDIO CONTROL register $80.
The Tx frequency is set using bits 0 to 12 in the CTCSS TX FREQUENCY register $83, using the formula
below:
A = fXTAL (Hz)
16 × fTONE (Hz)
Where A is the binary number programmed into the 13 bits.
When Bit 7 (in the first 8 bits) is set to "1" the tone output is set at VBIAS or NOTONE without regard to the
number "A" programmed. When Bit 7 is "0" the programmed tone is set on the output. Programming bits 0 to
12 to "0" sets the output to VBIAS. Powersave is also achieved by disabling the Tx (Bit 7 in the SUB-AUDIO
CONTROL register $80).
©1999 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480199.002
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA
All trademarks and service marks are held by their respective companies.
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