GENERAL INFORMATION
Software protection
To prevent accidental interference with the contents of internal memories, internal data is
protected by a secure key sequence.
Two levels of protection are offered, appropriate to the function being accessed. The
most secure is reserved for features which alter the calibration data of the instrument.
Spectral purity
With an SSB phase noise performance of typically -122 dBc/Hz at 470 MHz (20 kHz
offset), the NAV-750C can be used for both in-channel and adjacent channel receiver
measurements. Harmonically related signals and non-harmonics are better than -30 dBc and
-70 dBc respectively.
Calibration
The NAV-750C has a recommended two year calibration interval and is calibrated
entirely by electronically controlled adjustment. There are no internal mechanically adjustable
components to affect the calibration. The calibration display is available via soft key selection at
the utilities menu.
Date stamping
After readjustment the instrument updates the calibration data and records the date of
adjustment. The calibration due date can be set and when this date is reached a message advises
the operator to return the unit for calibration.
-50
-60
-70
-80
-90
-100
-110
-120
-130
-140
-150
-160
10
100
1k
10k
100k
1M
10M
Frequency Offset (Hz)
Carrier Frequency (MHz)
-100
-110
-120
-130
-140
10
20
50
100
200
500
1000
2000
C0079
SSB Phase
Noise (dBc/Hz)
SSB Phase
Noise (dBc/Hz)
Typical performance at 20kHz Offset
Typical performance at 500MHz
Fig. 1-1 Typical phase noise performance
1-5
