E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Harmonic Spurious
1-78
• Pin 1 +15 Vdc ±0.75 Vdc
• Pin 2 +5.2 Vdc ±0.5 Vdc
Table 1- 26 shows the amplitude ranges and the corresponding attenuator switch control line voltages. Attenuation
is switched in at +3 Vdc ±0.75 Vdc and switched out at 0 Vdc.
6. If the voltages are correct, replace the attenuator.
7. If the voltages are not correct, replace the A26 MID.
Troubleshooting Harmonic Spurious
Harmonics are multiples of the output frequency. The second harmonic should be two times the output frequency at
an x dBc down. This section contains procedures for checking spurious harmonic emission levels to make sure they
are within specifications.
NOTE If the harmonic falls beyond the frequency range of the signal generator, the harmonic is not specified or
measured.
To measure harmonics that fall within the signal generator frequency range, set the signal generator and spectrum
analyzer to the harmonic frequency and set the signal generator to a specified power level. Measure the output signals
peak power level on the spectrum analyzer. This peak power level is the reference level for the harmonic
measurement. Turn on Marker Delta, set the signal generator to the fundamental frequency, and measure the power
level of the fundamental frequency. The dBc value is the difference between the fundamental peak power level and the
harmonic frequency power level.
Table 1-26
Pin Numbers and Voltages
Amplitude
Levels
J13–5 40B dB
Atten. Step
J13–6 20 dB
Atten. Step
J13–7 40C dB
Atten. Step
J13–9 10 dB
Atten. Step
J13–10 5 dB
Atten. Step
+25 to +5.1 dBm 0 0 0 0 0
+5.0 to –4 99 dBm 0 0 0 0 +3
–5.0 to –14.99 dBm 0 0 0 +3 +3
–15.0 to –24.99 dBm 0 +3 0 0 +3
–25.0 to –34.99 dBm 0 +3 0 +3 +3
–35.0 to –44.99 dBm +3 0 0 0 +3
–45.0 to –54.99 dBm +3 0 0 +3 +3
–55.0 to –64.99 dBm +3 +3 0 0 +3
–65.0 to –74.99 dBm +3 +3 0 +3 +3
–75.0 to –84.99 dBm +3 0 +3 0 +3
–85.0 to –94.99 dBm +3 0 +3 +3 +3
–95.0 to –104.99 dBm +3 +3 +3 0 +3
>–105.0 dBm +3 +3 +3 +3 +3
Table 1-27 Harmonic Specifications
Harmonic Specifications
< 10 MHz –28 dBc
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