TB 9-6625-2273-50
(using TI control knob) for maximum signal amplitude. Adjust R5050 and R5060 (fig. 1) for
minimum signal amplitude. Signal amplitude will be ≥ 40 dB below reference point
established in (7) above. If not, adjust R1060 (fig. 1) for minimum signal amplitude (R).
(16) Adjust spectrum analyzer controls to view 3d harmonic (435 MHz) of TI output
signal. Signal amplitude will be ≥ 40 dB below reference point established in (7) above.
(17) Set TI output frequency to 295 MHz and repeat (9) through (16) above until no
further adjustments are required.
NOTE
Dc blocking capacitor will cause some attenuation of signal
below 300 kHz.
This attenuation will reduce apparent
harmonic performance by several dB.
(18) Press TI pushbuttons as listed in (a) through (c) below:
(a) AMPL and enter 5 V on DATA keyboard.
(c) OUTPUT HEAD ON/OFF (turn the output ON).
(19) Adjust spectrum analyzer controls to view TI 50 kHz output signal. Adjust
spectrum analyzer controls to establish amplitude reference point of TI output that will
permit a measurement at least 55 dB below reference point. Note reference point.
NOTE
Do not change amplitude reference level on spectrum analyzer
during the remainder of this procedure.
(20) Adjust spectrum analyzer controls to monitor 2d (100 kHz) and 3d (150 kHz)
harmonic of TI output signal. Signal amplitude will be ≥ 40 dB below reference point
established in (19) above. If not, adjust R5070 and R1090 (fig. 1) for best 2d and 3d
harmonic performance (R).
NOTE
It is necessary to compromise the 2d and 3d harmonic
performance and all higher order harmonics so 2d and 3d
harmonics are -40 dBc or better and the higher order
harmonics are -55 dBc or better. To achieve the best amplitude
flatness, the 3d harmonic should be slightly lower than the 2d
harmonic.
(21) Adjust spectrum analyzer controls to view 4th (200 kHz) and 5th (250 kHz)
harmonic of TI output signal. Signal amplitude will be ≥ 55 dB below reference point
established in (19) above.
10
