HP (Hewlett-Packard) HP 85660B ユーザーズマニュアル

Since these RC combinations have long time constants, they cannot readily respond to the
transients produced at band crossings and scan resets. Therefore, whenever the sample and
hold circuit is holding, R24 to R26 are shorted by Q4 to 

 respectively.

 and 

 and their associated circuitry form -9 V and 

 V reference supplies used in

the YTX Driver, and elsewhere in the A6 RF Module.

4