Analog Signal Processing; Unit Control - Motorola MR 11 Service Manual

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MR 11

3.5 Analog Signal Processing

NF 134
The AF module NF 134 contains all the electronic level adjusters required for adjustment as well
as all the AF filters for the transmission and reception paths of the various channel spacings.
Microphone Amplifier ML 11, HA 11, HBT 11
A new kind of AGC amplifier is used which enables good communication even in noisy environments
(DNC, Dynamic Noise Compensation). The external inputs (MIC100) of the radios are unstabilised
and only obtain their DNC function from a connected Motorola hand control unit.
AF Output Amplifier
The AF output amplifier for the external loudspeaker and the hand control unit is a monolithic IC
TDA 1020 (N403). Four Watts on 4 ohms are generated.

3.6 Unit control

The unit control consists of a computer system with internal and external memories. The ASIC
MDSR 134 can be considered the central element. It is used for clock generation for other
components, provides the Chip-Select signals of the memories, has a port extension and analog
and digital encoders/decoders.
Microcontroller
A 16-bit controller from Mitsubishi is used here. Its designation is: M37710. It is operated with
approx. 15 MHz. This computer contains a 32 kB internal ROM.
The so-called "MELP-SW" (Micro Electronic Processor Software) needed for radio tuning, loading
the actual radio software and communication with the coding program "WinIPP" is located in the
inernal computer memory.
Memory
A 32 k RAM and two slots for flash EEPROMs are provided as external memory components. Two
times 256 kB or two times 512 kB can be plugged in here. An EEPROM of 2 kB serves as a
parameter memory. General access to all memories is through the MELP-SW.
Software
The entire radio software is divided into two parts. The unchangeable MELP-SW and the radio-
specific FLASH-SW. This MELP-SW controls general access, contains extensive test sequences,
the necessary hardware drivers and supports the production-relevant test routines. The system is
always started under MELP-SW.
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