(c)  
The dc output of the phase detector is converted to 400 Hz in a chopper, amplified and applied to drive the servomotor. The servomotor is geared back to the phase shifting resolver. The motor turns the resolver until a null output is obtained from the phase detector. When the two inputs to the phase detector are in phase quadrature (90 degrees out of phase), a null output is obtained and the motor stops. The resolver shaft is then correctly positioned to indicate the VOR radial on which the airplane is flying. The servomotor also drives the omnibearing indicator (OBI) dial and the rotors of the RMI synchro and the VOR resolver.

 (d)  
The RMI synchro receives magnetic heading signals from the Magnetic Heading Reference System via either the ADF RMI or the VOR/DME RMI and resolves these signals to produce the VOR bearing signal which is applied to position the VOR indicator needles of the VOR/DME RMI.

 (e)  
The VOR resolver accepts course select signals from the course resolver in the AP/FD mode select panel via the VOR/ILS A transfer relay. The output of the VOR resolver is applied to to the manual detector which has a 400-Hz signal for a reference input. The output of the manual VOR and ambiguity detectors consist of the VOR deviation and to/from signals which are applied to the flight instruments and AP/FD system.

 (f)  
The outputs of the integrity monitor circuits control the flag relays. When the receiver is operating properly and processing valid VOR/ILS signals, the relays energize to provide the VOR/LOC and GS super flag output signals.

 (4)  
BENDIX RNA-26C Receiver, Localizer Operation

 (a)  
Tuning to an ILS frequency on the VHF NAV control panel grounds the ILS energize circuit and energizes the VOR/LOC mode relay in the receiver. This relay action provides the ILS 28 VDC mode voltage output and enables the localizer and glide slope 90/150 Hz deviation circuits.

 (b)  
In localizer operation, the 90/150 Hz signal output is fed to the localizer course deviation displays in the flight instrument and AP/FD systems. The integrity monitor continuously monitors operation of the localizer circuits and produces a localizer warning (flag) if a malfunction occurs.

 (5)  
Bendix RNA-34A Receiver, VOR operation,

 EFFECTIVITY

 AF 101-120, 123-154,  CONFIG 1 172-173, 191-194; GN ALL;  02 Page 10 LH ALL AND MD ALL  Sep 25/94

34-31-00
 (a)  
Frequency select information from the control panel is processed in the microprocessor. These signals are used to control operation of the synthesizer which provides the required injection frequencies and tuning voltages for the VHF tuner. For VOR operation, navigation signals selected by the tuner are processed into a composite NAV signal. This composite signal is fed to VOR signal processing circuits and to an audio amplifier. The audio output is provided to the flight interphone system (23-51-00).

 (b)  
The VOR signal processing separates the 30-Hz variable and 30-Hz reference-phase signals from the composite signal. The two 30-Hz analog signals are then converted to digital signals which are compared in the microprocessor to determine the phase difference which represents the bearing to the VOR station. The bearing to the VOR station is supplied in sin 0/cos 0 format; in digital format; relative bearing to the RMI

--
in XYZ format; and as a composite NAV signal. For manual VOR,
 the external course resolver is set to the desired course. The
 resolver output is fed through an analog-to-digital converter
 to the microprocessor. The microprocessor compares the
 selected course with the VOR bearing and produces a left/right
 course deviation voltage that is fed to the HSI. Additionally,
 the microprocessor resolves the VOR ambiguity and produces
 either a TO or FROM voltage which is fed to the HSI to activate
 the appropriate indication. In addition, the microprocessor
 continuously monitors operating conditions of the VOR circuitry
 and produces a NAV warning (flag) if a malfunction occurs.
 (6)  Bendix RNA-34A Receiver, Localizer Operation
 (a)  
In localizer operation, the 90-Hz/150-Hz signal output of the VHF receiver is fed through filters to the ILS multiplexer. The output of the multiplexer is fed through an analog-to-digital converter to the microprocessor. From this signal input, the microprocessor develops course deviation voltages that are fed to the course deviation displays in the flight instruments. The microprocessor also continuously monitors operating conditions of the LOC circuitry and produces a LOC warning (flag) if a malfunction occurs.

 (b)  
　
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