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Version 4 27 Feb 08
REI MDC-2100/MDC-900 16
Technical Bulletin
24 April 2002
For the MDC-900 and MDC-2100
This bulletin describes a calibration process to ensure the maximum technical
performance for the MDC unit.
Technical Background:
Most Down-converter products contain a local oscillator (LO) reference signal that is
utilized in the down-conversion process. While this LO frequency is vital to the down-
conversion process, it also creates a blind spot in the frequency spectrum that cannot be
analyzed. However, the MDC and OSCOR design addresses this technical problem. In
order to ensure that there is not a blind spot at the LO frequency or any of it’s harmonics
(6GHz, 12GHz, 18GHz), the OSCOR automatically shifts the LO frequency as it is
sweeping through the frequency range near the LO frequency. The ability to automatically
shift the MDC LO frequency as commanded by the OSCOR is one of the primary reasons
that the MDC units were designed only for use with the OSCOR. Other spectrum
analyzers do not contain the intelligent functions to control this function and remove blind
spots created by the LO. In order for this shifting process to be optimized, it is necessary
to calibrate the OSCOR shift command with the physical characteristics of the MDC
frequency shifting process. However, even if the calibration process is not performed, the
probability for a random signal of 200KHz bandwidth to actually be located in a blind spot
assuming a uniform random signal distribution is only 0.000167.
Calibration Process:
Follow these steps to calibrate the MDC to the particular OSCOR utilized with it. There is
no need to connect the MDC to the OSCOR for calibration.
To calibrate an OSCOR to a specific MDC unit;
1. Press SHIFT and the numbers 786.
2. Enter the number ________
. This calibrates for 6GHz. This number is unique to each
MDC unit and must be obtained from REI. The above calibration number is to be
used with MDC-900/MDC-2100 serial number ____________
. To calibrate for 12GHZ
enter ________
. To calibrate for 18GHz enter ________.
3. Press Shift and the numbers 788 to permanently store the calibration data in the
OSCOR.
Note: This calibration data is permanently stored in the OSCOR Kernel. It will never need
to be repeated even if the OSCOR program key is replaced. The calibration process can
be repeated as often as desired. Also, if the MDC is used with another OSCOR, the
calibration process must be repeated to ensure that the MDC and OSCOR are calibrated
for use together. The OSCOR will store only one calibration number at a time.