Rf Modulator Module Description; Modulator General Operational Description - Aeroflex NAV 2000R Operation Manual

The first term is a carrier signal with the frequency modulated reference. The second term is the variable
signal and the third term is the identification (ident) signal. The VOR ident signal may be used to
generate Morse code.
modulated carrier and two variable amplitude tones.
The alternate mode sums three individual tones with variable amplitudes.
describes the alternate mode:
A 1 SIN(w 1 t i ) + A 2 SIN(w 2 t i ) + A 3 SIN(w 3 t i )
where
A 1 = Amplitude of the tone 1 signal.
A 2 = Amplitude of the tone 2 signal.
A 3 = Amplitude of the tone 3 signal.
w 1 t i = Instantaneous phase of tone 1.
w 2 t i = Instantaneous phase of tone 2.
w 3 t i = Instantaneous phase of tone 3.
The first term is the instantaneous amplitude of tone 1.
instantaneous amplitude of tone 2 and tone 3.

4.3.8 RF MODULATOR MODULE DESCRIPTION

The RF modulator module amplitude modulates (AM) a CW carrier input with an audio input signal and
provides control over percent modulation and average power output.
The RF modulator module consists of an audio board, an RF modulator board, and a programmable step
attenuator. The modulation of a CW carrier is achieved by applying the CW signal to the RF modulator
board where it is modulated by signals appropriately conditioned for percent modulation by the audio
board. The output power is leveled on the RF modulator board and the desired output power level is
achieved by switching in sections of the programmable step attenuator, for each 1 dB step and by moving
the reference voltage controlled by the leveled output power for each .1 dB step.
The boards are interfaced to the NAV 2000R system computer via the audio board which controls the RF
board and step attenuator. An in depth treatment of the modulation process is provided in the following
sections.
JPN Drawing 40-9520-51 (located in Section V of this manual) shows the Block diagram of the RF
Modulator Module. An operational explanation of the process of modulation and a functional description
of each of the module components follow.

4.3.9 MODULATOR GENERAL OPERATIONAL DESCRIPTION

The general operation of the NAV 2000R RF modulator module is discussed in this Section. Also
reference JPN Drawing 40-9520-51 (located in Section V of this manual).
The module consists of an audio board, an RF board, and a programmable attenuator. An RF carrier is
applied to the RF input port via the mother board. This CW signal is generated within the synthesizer
module.
NAV 2000R SIGNAL GENERATOR - REV. 0 – JULY 26, 2007 - PG 4-6
Aeroflex Operation Manual
VOR is a complex signal which combines a variable amplitude frequency
The following equation
The second and the third term are the