*8656B Specifications:

Frequency Range : 100 kHz - 990 MHz
Frequency Resolution : 10 Hz
Output Accuracy : +/- 1.0 dB
Output Range : -127 dBm - +13 dBm
Output Resolution : 0.1 dB
Programmable Interface : -126 dBc/H
SSB Phase Noise Range : HP-IB - -114 dBc/H
Time Base Stability : +/- 2ppm