Standard Features; Programmable Channel Spacing; Programmable Dcs / Ctcss Encoder / Decoder; Description - RELM BK RADIO SDMX920 Technical Manual

Base station and repeater
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MX920 Base Station & Repeater

3. Standard Features

3.1 Programmable Channel Spacing

The MX920 receiver can be programmed for either 12.5 kHz (Narrow Band) or
25 kHz (Wide Band) channel bandwidth. Switchable IF filters in the receiver and
automatic 12.5 kHz / 25 kHz gain compensation in the audio paths make the change in
bandwidth transparent to the user.
With the switchable IF bandwidth receiver, each channel is programmed as either
12.5 kHz / 25 kHz via the Channel Edit screen.

3.2 Programmable DCS / CTCSS encoder / decoder

3.2.1 Description

The MX920 is fitted with a full duplex DCS / CTCSS encoder / decoder. There are 83
DCS codes available. Any standard DCS code or CTCSS tone may be assigned to any
of the transmit or receive channels through the channel edit screen in built-in radio
configuration menu system. The decoder is extremely flexible allowing for predictive
and non-predictive modes and any valid CTCSS tone to be decoded. Any standard TX
CTCSS tone may be associated with the programmed decode tone through the channel
edit screen in the radio configuration menu system. Multiple CTCSS tones are
programmable for any channel providing "Community Repeater" functionality.
The DCS encoding function provides continuous, repetitive digital word modulation
to the transmitter. The decode function controls receiver muting to eliminate all calls
that are not coded with the assigned DCS code.
3.3 Local Speaker, Mic Socket and Front Panel
Mute / Squelch Controls
3.3.1 Description
For applications needing a user interface at the base station the MX920 comes with a
local speaker, microphone socket, front panel mute / squelch and volume control. The
full implementation is described in Section 1.1.1.1. This section describes the fitted
parts.

3.4 Local Channel Change

3.4.1 Description
For applications needing a user interface at the base station the MX920 include local
channel change via the front panel push-wheel switches. The full implementation is
described in Section 1.1.1.1 this section describes the parts fitted.
Technical Manual
2003 Revision

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