Skanti TRP 5000, Инструкция по эксплуатации

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The Side-step principle is performed as follows. Assume that the output
frequency of the Frequency Synthesiser is (a.b.c.d.,e) KHz. Th is
frequency is divided by (abcd + 1)e times and (abcd) * (10-e) times, so
that the division ratio on the average is: ((abcd + 1)* e + (abcd)*(10 -
e)) = abed.e. Thus the average output frequency of the variable counter
chain will become equal to the 1 KHz reference frequency of the loop, as
it should, if the loop is properly locked.
5.3.6 The injection frequency to the 2nd. mixer of the RF Translator is
supplied by the Harmonic Generator /235\. The frequencies are all
harmonies of the 1.4 MHz (or 1,973 MHz) reference frequency. The desired
harmonic is selected by a Band Selector control- led from the Memory.
The Band Selector also selects the correct band-pass filter and level
setting potentiometer of the RF Translator.
The Memory /238\ in which the necessary information associated to each
frequency No. is stored controls the synthesiser and the Harmonic
Generator, and supplies information to the Band indicator of the
Transmitter Power Amplifier. The memory address is selected from board
/239\ which contains the keyboard and a display showing the selected
Frequency No.
The 1,4 MHz (or 1,973 MHz) reference frequency is normally supplied from
the master oscillator of the receiver. However, if the receive r is not
installed in the cabinet, Master Oscillator /240\ (or /240a\ is
available for mounting in the Exciter.
5.4 Circuit Description, Exciter E 5000 or E 5001
5.4.1 /232\ 1.4 MHz (or 1,973 MHz) EXCITER
The AF input signals are connected to the compressor through an input
selector. The microphone and line inputs are open only if the terminals
4and 8 are both HIGH. The telex AF input is open only if terminal 8 is
LOW. The tone input is always open.
The gain of the compressor is controlled by means of the field effect
transistor TR2, which functions as a variable emitter resistor for the
left hand transistor in IC1. The control voltage is provided by a
rectifier consisting of the pair of ICI transistors to the right, which
detect the side-band level at the output of the crystal filter X1. When
terminal 4 is LOW the compressor is off, as the resistance of TR2 is
kept at its maximum value.
The compressed audio signal and a 1.4MHz (or 1,973 MHz) signal from the
carrier level regulator IC2 are fed to the balanced mixer IC3. The
output is a 1.4MHz (or 1,973 MHz) double side-band suppressed carrier
signal, which is amplified in TR4 and fed through crystal filter X1 that
removes the upper side-band and suppresses the carrier still further.
The gain of the amplifier stage following the filter is controlled from
terminals 13, 14, and 15 by inserting different emitter resistors. In
the A3H-rnode all terminals are HIGH and the gain is determined by R70.
Carrier re-insertion is performed by applying the 1.4MHz signal from the
carrier level regulator to TR6 via an attenuator controlled from the
same terminals.
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