2948B is the low noise model of 2945B, the phasic noise of source of its radio frequency hadquency had very big improvement than 2945B, can use at measuring tape receiver accurately.

• 2948B是2945B的低杂讯型号，其射频源的相位杂讯比2945B有了很大改善，可用于切确测量窄带领受机。分量轻便于携带及野外测试；