Installation guide

Troubleshooting
Troubleshooting Harmonic Spurious
1-101
Troubleshooting Harmonic Spurious
Harmonics are multiples of the fundamental output frequency produced by a signal generator. Specifically,
the second harmonic is two times the output frequency and its amplitude is measured relative to the
fundamental (carrier) output frequency’s amplitude; the power level of a harmonic is expressed as −xx dBc.
• If the frequency of a harmonic falls beyond the frequency range of a signal generator, that particular
harmonic is not specified or measured.
• If the frequency of a harmonic falls within the frequency range of a signal generator, the harmonic’s power
level is obtained with the following procedure:
1. The signal generator and spectrum analyzer are initially set to the same harmonic frequency.
2. The signal generator is also set to a specific power level and its output peak power level is measured on
the spectrum analyzer; this peak power level is the reference level used for the harmonic
measurement.
3. The signal generator is then set to the fundamental frequency and the power level of the fundamental
frequency is measured by using
Peak Search and Marker Delta.
This measurement obtains the power level of the harmonic and is expressed as a dBc value; it is the
difference between the fundamental peak power level and the harmonic frequency power level.
Troubleshooting Harmonic Spurious by Fundamental Frequency
Because the RF Output frequency is derived from a mixer on the A13 Output and the A14 Extended
Frequency Output (Option 506), harmonic spurious problems are determined by the frequency range of their
fundamental frequency.
Fundamental Frequencies ≤ 250 MHz
Problems with the RF Output frequency ≤ 250 MHz are most likely the A13 Output.
Fundamental Frequencies > 250 MHz and ≤ 3GHz
Problems with frequencies > 250 MHz and ≤ 3 GHz are best determined by measuring the harmonic levels at
both the RF Output and the Coherent Carrier outputs with the following procedures:
• “To Verify Harmonic Performance at the RF Output” on page 1-102
• “To Verify Harmonic Performance at the Coherent Carrier Output” on page 1-103
Fundamental Frequencies > 3GHz
The harmonic frequency is outside the upper frequency limit
of the Agilent E4438C ESG vector signal generator and is therefore not specified.