Calibration; Memory Usage And Initialization - Aeroflex NAV 2000R Operation Manual

4.4.2 CALIBRATION

When the calibration procedure is entered, the system computer is directed to setup the DSP board and
Modulator for each step of the procedure as it is displayed and followed.
For the first steps of internal audio, and Modulation alignment, the system computer tells the DSP board
to generate a 1000 Hz sine wave, and tells the Modulator to set % MOD to 50.0% and RF level to -10
dBm. During the RF level alignment, the system computer turns off audio from the DSP board. During
the External Modulation alignment, the DSP is told to turn off all internal audio, and the modulator is told
to turn the external MOD AUDIO INPUT on.
During VOR Bearing calibration, external MOD audio input is switched off, and the DSP board is told to
generate a VOR composite audio with a bearing of zero degrees. Modulation is set to the nominal VOR
levels. The error value loaded by the user is used to calculate a calibration factor which is stored within
the system computer and passed to the DSP board. The DSP shifts the phase of the VOR signal by this
calibration factor. This factor will be used during all VOR generation until it is changed by the NAV 2000R
user within the CAL procedure.
Finally, upon going to the next and last calibration step, the DSP board is told to generate a 1000 Hz
tone.
Upon completing CAL, the NAV 2000R will return to the Utility Menu.

4.4.3 MEMORY USAGE AND INITIALIZATION

The NAV 2000R internally contains non-volatile memory to maintain it's setup after it is powered off.
System configuration, current and registered parametric settings, and calibration data constants are some
of the items stored within the battery backed RAM.
integrated battery backed-up static RAM module. If, for whatever reason, the battery RAM module is
replaced, the part must be re-initialized.
To initialize the part the user must: 1) Re-initialize the 49 registers to update the data integrity of each. 2)
Re-initialize the unit "on-time" clock and number of times unit has powered up counter. 3) Re-configure
the NAV 2000R to the user's preference. 4) Re-calibrate the unit to insure good calibration constants.
Dependent upon the BATRAM's initial data settings, the NAV 2000R may power up with a blank screen
and a "** BOOT ROM **" annunciation toward the bottom portion of the display. If this occurs, press the
120 degree bearing "hot key" to force the unit to complete the power up, which will cause the JcAIR logo
to be displayed and the unit power-up self test to execute, before proceeding.
1) Re-initialize the registers to update data integrity:
In the event the battery RAM is replaced with a new part, the power up self test of the NAV 2000R will fail
the CPU RAM register memory test. This tells the user that one of the set-up registers contains bad data.
To re-initialize the registers, one could save the current paged parametric data to each of the available
locations by using the STO key (store) function for each of the available locations. This would re-write
every register insuring good data for each. However; there is another way to clear the registers from
within the Utility Menu. Push and hold one of the mode switches to request the unit to list the utility
menu options. Option 7, SET ALL REGISTERS TO DEFAULT, will automatically clear all registers to
factory default settings in one step. After pressing option 7, the system will require you to verify the
clearing procedure by pressing the CLR (clear) key.
NAV 2000R SIGNAL GENERATOR - REV. 0 – JULY 26, 2007 - PG 4-13
Aeroflex Operation Manual
The non-volatile memory module, U14, is an
NOTE: