Honeywell
COMPONENT MAINTENANCE MANUAL
PART NUMBER 964-0452
1I.B.1516A Page 42
Mar 30/01
23-12-01
Gates, D9-B and D9-C, link the SENS2 and U2.2 signals in such a way that BI-
TAMP = H, and therefore, a fault is reported in Amplifier Board, A31, if the ALC
vottage is in the normal range below 5V, but the HF voltage present at the output
of Amplifier Board, A31, is still too LOW (SENS2 = HI). The BITAMP signal is
also valid only during the BIT routine, and this is the only time when it is inquired
by Controller, A8.
The continuous monitoring of Power Amplifier, A3, includes permanent compar-
ison of the RF voltages at the input and output of Power Amplifier, A3, with their
set values and setting CMAMP = H, if the level is sufficiently high at the power
amplifier input (SENS1 = L), but not at the output.
The FORWARD signal, which is an image of the HF envelope, undergoes peak
detection via V46, C176, and R176 with a very short charging time constant and
a discharge time constant of 4.7ms. This rectified signal is compared with the
set point value SPRFP divided by R187 and R182 at comparator U1-D. If the
output power is too LOW, U1.2 switches to H level, and CMAMP becomes H as
a result of linking with SENS1 via gates, D6-D and D9-A (i.e., Power Amplifier
A3, defective), if at the same time SENS1 = L.
Like CMTEM, the CMAMP signal also initiates an L pulse to CMINT via D5-A,
and therefore, actively triggers an inquiry by Controller, A8, via the data bus.
In addition, the CMAMP signal switches OFFthe operating points (OPON = L,
OPOFF = HI via gates D8-D, D8-E, D13-D, D7-A, D14-A, and D7-F in the event
of a fault, that is to say, when CMAMP = H.
The response time of this protective circuit is delayed by means of R209 and
C93 in order to provide sufficient time for measurement and fault localization
during the BIT routine.
(c)
Harmonic Filter, A32
1
General
A32 is composed of 7 filters, a directional coupler, a transmit/receive relay, a BI-
TREL circuit breaker, and a modem. Ref. Fig. 21 for block diagram
2
Low-Pass Filter
The 3-stage Cauer low-pass filter is designed to attenuate the harmonics gen-
erated by the amplifier to an interval stated in the data sheet. Of the 7 filters, 6
are connected via relays at the inputs and outputs. The 7th filter with the highest
frequency range can either be connected separately by a relay at the input or
series connected to the other filters. Depending upon the operating frequency
on1 or 2 filters are in operation. The relays are actuated by FETs, which in turn
are driven by the FILT1 to FILT7 signals.
3
Directional Coupler
A forward and reverse voltage are tapped from the directional coupler. These
voltages are rectified by forward and reverse diodes, V36A and V31A, respec-
tively. Diodes, V31B and V36B, serve to provide temperature compensation.
The direct voltages are amplified by N1A and N1B. The forward and reverse di-
rect voltages FORV and REVV, thus generated, are directly proportional to the
forward and return power.
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