TM
11-6625-524-14-4
OPERATING INSTRUCTIONS
GENERAL
T h i s chapter should be read carefully before using the voltmeter. It contains infor-
m a t i o n necessary for proper operation of the voltmeter. To achieve valid readings,
p r o p e r switch settings are required. C o n t r o l s , with the function of each, are listed
in paragraph 3-4. The controls are shown in figures 3-1 and 3-2. Operating pro-
cedures are described in paragraph 3-5.
POWER LINE REQUIREMENTS
The voltmeter can be used on either 115 or 230V AC power line. A line voltage
s e l e c t o r slide switch, located on the serial/power plate, must be set to agree with
the line voltage to be used.
The voltmeter will operate on power line frequencies from 45Hz to 1000Hz. Unless
o t h e r w i s e specified, t h e AC line rejection (input) filter, is adjusted for use on a
60Hz power line frequency. F o r operation on another power line frequency, it is ad-
visable to retune the filter.
GENERAL PRECAUTIONS FOR RF MEASUREMENTS
NOTE
Maximum Allowable Overload: Damage to the diode cartridge may result should
t h e following input limits be exceeded:
DC: 400V
RF: 15V RMS or 42V P-P
NOTE
T h e manufacturer's warranty does not apply to burned-out diode cartridges.
a. Overload recovery: Should any range be momentarily overloaded, especially
t h e more sensitive ranges, it is advisable to turn the RANGE switch to the 0.03v
full s c a l e p o s i t i o n t o f a c i l i t a t e a f a s t e r o v e r l o a d r e c o v e r y .
b . P o w e r d i s s i p a t i o n r a t i n g : T e r m i n a t i o n adapters are designed for 5 watt dis-
sipation. Do not exceed 5 watt RF.
c. M i s - t e r m i n a t i o n : High frequency signal generators have terminated output
t r a n s m i s s i o n lines. T h e terminating resistance, c o r r e s p o n d i n g to the character-
i s t i c s impedance of the transmission line, i s usually installed between the out-
put terminals at the free end of the transmission line. Some generators may have
t h e transmission line terminated in its characteristic impedance internally at the
o u t p u t connector. In this case, i f the external transmission line is also in 50 ,
serious measuring errors may result. T O avoid this mis-match, the user must check
t h e generator in question to determine if the line is internally terminated. If
s u c h is the case, the resistor should be disconnected, allowing the 50 termination
o f the voltmeter's probe to become the required output matching resistance. If it
i s not desirable to remove the internal termination resistor, an open circuit
adapter should be used.
d. Measurements using the Hi Impedance Tip: Care must be exercised in measuring
l o w signal levels because of possible stray RF pick-up. The lowest level at which
t h e tip is useful will depend upon the strength of the stray RF field. Since the
probe is a very wide-band device (20KHz to 600MHz), any RF signal present within the
probe's response (AM-FM-TV broadcasting. point-to-point communications, etc.) may
Plus the probe's shunt capacitance, may cause resonances, c r e a t i n g large measuring
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