HP 86290B扫描振荡器频率参考值最高可达18.8伏

我有一个带选件H08的HP 86290B。
该扫频振荡器插头的频率从2 GHz到22 GHz。
但是，使用我的DVM测量时，设备背面BNC连接器的频率参考值最高可达18.8伏。
我认为应该产生大约1伏/ GHz的输出，这样电压应该高达22.0伏？
然而，我检查了输出频率，它在刻度结束时确实达到了22 GHz。



     以下为原文

  I have an HP 86290B with option H08. The frequency of this sweep oscillator plug goes from 2 GHz to 22 GHz.  However, the frequency reference from the BNC connector on the back of the unit only goes up to a maximum of 18.8 volts when measured using my DVM. I thought it was supposed to produce an output of about 1 volt/GHz so that the voltage should go up to 22.0 volts?  I checked the output frequency, however, and it does go to 22 GHz at the end of the scale.