The HP 8601A is a signal generator and sweeper system used as part of the collection of network analyzers from the 90s. It's a wide range RF signal generator that covers frequencies from ~100 kHz to ~100 MHz. It is also capable of sweeping the frequency range with various modes and power levels. The instrument is quote modular and has several independent RF sections that can be serviced or replaced separately. The abundance of RF shielding also greatly reduces the noise and RF leakage of the instrument.