MTR3000 Station Control Module: Functional Theory of Operation 5-5
5.2.3 MAKO
MAKO IC is a customized IC and the SCM uses this device to leverage some unique functionality
that it provides.
Most of the MAKO functionalities are not used on the SCM. Only the MAKO codec, USB driver, ADC,
DAC, and some voltage regulators are used on the MTR3000 Base Station/Repeater. The 9 channel
general purpose ADC is used for various controller metering.
5.2.4 Field Programmable Gate Array (FPGA)
The SCM FPGA includes the following major functions:
• External reference watchdog
• SPI Address decoding and buffering
• TCXO Phase detection and compensation
• Clock generation
• Reset controller
• External Interface (Wireline SSI, LED, etc.)
FPGA field upgrade capability is also supported on the MTR3000 Base Station/Repeater.
5.2.5 Audio
There are four transmit inputs: Tx Audio, Tx Audio-Pre & Tx Data on the backplane interface board
25-Pin connector, and the microphone input on a front panel RJ45 connector.
Tx Audio is a flat (not pre-emphasized) input which is used if the incoming transmit audio signal is
already pre-emphasized or if pre-emphasis is not needed. The Tx Audio-Pre input provides a
hardware pre-emphasis filter. The Tx Data input is used for low speed data, Private-Line (PL) and
Digital Private Line (DPL) signals.
The Tx Audio, Tx Audio-Pre and microphone inputs pass through a hardware modulation limiter and
splatter filter before being summed with Tx Data, with the Tx Data bypassing the limiter and splatter
filter. This summed signal is applied to the MAKO codec “mic” input. The audio signal without Tx
Data is provided on the MAKO codec “aux_mic” input.
There are three receive outputs: Rx Audio & Aux Rx Audio on the backplane interface board 25-Pin
connector and speaker audio on a front panel RJ11.
The speaker audio is the sum of the MAKO codec output (demodulated audio) and transmit audio. A
high pass filter removes any data, PL or DPL from the speaker audio. A programmable attenuator is
used to adjust the speaker audio level before being output on the RJ11 connector.
Aux Rx Audio is the output of the MAKO codec (demodulated audio), and Rx Audio is the sum of the
MAKO codec output and the microphone audio.
Refer to Figure 5-2 for audio paths and voltage levels.
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