KROHN-HITE 3988 贝塞尔(Bessel)线性相位滤波器及巴特沃斯滤波器用于电测仪器，放大电测仪器（示波器,波形发生器,滤波器）的功率电压并减少谐波,MODEL3988与7602M和信号发生器相连，将信号发生器的输出信号放大，KROHN-HITE 3988用于无损检测激发超声波。

Model 6620A
Precision Phasemeter
• Accuracy: Typically 0.02°
• Resolution: 0.01°
• GPIB Programmable
• Automatic Ranging Display
• Automatic Voltage Ranging
• Input Voltage Range:
• 10mV rms to 320V rms
• Deviation Measurements
• Accepts Any Waveform
• Analog Output
• Automatic Meter Correct (AMC)

PERFORMANCE
The Model 6620A provides precision phase measurements with a
typical accuracy of 0.02° and a resolution of 0.01° over most of
the frequency range. It will accept a wide range of input signal
levels from 10mVrms to 320V rms and input waveforms
including sine,  square and pulses. A 5 digit LED display
provides continuous direct readout of phase angles between 0.00°
and 360.00° or ±180°. These two ranges can be manually or
automatically selected.
UNIQUE DESIGN
Two common factors that will affect the accuracy of a phasemeter
are distortion and/or broadband noise present on either or both of
the input signals. A unique circuit design used in the 6620A
significantly reduces any effects that may be caused by these two
factors.
Another problem found in most phasemeters is the inability to
respond to very small phase angles, resulting in fluctuations or
inconsistencies in the meter reading (sometimes referred to as
ambiguity). To overcome this problem, the 6620A uses a design
that eliminates any ambiguities that may occur at readings near 0°,
180° and 360°, and allows measurements as small as 0.01° to be
made

ACCURACY
Sinewave:
Input Volts (rms) Frequency Range Accuracy
10mV to 32mV 1Hz to 10kHz 0.2º
10mV to 100mV
10kHz to 50kHz 0.35º
50kHz to 10MHz 0.7º/100kHz
32mV to 100V
1Hz to 10Hz 0.1º
10Hz to 10kHz 0.05º
100mV to 100V
10kHz to 50kHz 0.05º
50kHz to 100kHz 0.35º
100kHz to 10MHz 0.35º/100kHz
100V to 320V
1Hz to 10Hz 0.2º
10Hz to 5kHz 0.1º
Squarewave: Double the specificatio

源自：深圳市湾边贸易有限公司