Field Alignment Procedure; Standard Test Equipment - RF Technology Eclipse Series Operation And Maintenance Manual

6

FIELD ALIGNMENT PROCEDURE

U908 is set up as an inverter, and uses the 12V rail to create –12V.
U909 converts the +12V rail to +5V for all the digital circuitry.
The +12V rail is used to power the two on-board relays, as well as up to one extra off-
board relay. It is also dropped, via a linear regulator (U910) to produce the +10V rail,
which in turn is dropped by another linear regulator U911 to produce +5Q, which, in
turn, is dropped by a further linear regulator (U912) to produce +2.5V.
Similarly U913, U914, and U915 are linear regulators that produce –10V, -5V, and –
2.5V from the –12V output of U908.
+10, +5Q, and +2.5V, -10V, -5V, and –2.5V rails are used in the audio and RF sections.
D911 is a 4.096V (3%) reference diode. Its output is buffered by U906 which then
produces a reference voltage rail Vref, which is used by the CPU's A/D converter, and
the DACs, and also in the voltage to current converters of the VCAs (see Sheet 4, and
Sheet 7).
6 FIELD ALIGNMENT PROCEDURE
6.1

Standard Test Equipment

Some, or all of the following equipment will be required:
• AF signal generator, 75 - 3000Hz frequency range, with output level set to 387mV
RMS and, if the microphone input is to be tested, 10mV rms output.
• Power supply set to 28Vdc, with current >10A.
• RF 50 Ω load(s), 250W rated, return loss <-20dB, and total attenuation of 50dB
• Reference Oscillator. At least +5dBm output.
The external reference frequency is limited to:
500kHz, or any multiple,
any multiple of 128KHz greater than or equal to 4,
any multiple of 160KHz greater than or equal to 3
The accuracy should be at least 0.5ppm, preferably 0.1ppm
• RF Peak Deviation Meter
• True RMS AC voltmeter, and a DC voltmeter.
• RF Power Meter (accurate to 2%, i.e. 0.17dB)
• Some means of measuring Reverse Power, and a known 3:1 mismatched load.
RF Technology T50
6.1 Standard Test Condition
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