User Manual
14 
RS-232C CONNECTOR :      
Connector for serial interfacing with a computer. 
3-2. Operating Instruction 
Below is the basic operating information needed for frequency counter.   
a. Connect the unit to AC power cord into receptacle on rear panel and   
  plug into AC inlet. 
  b. To Turn on equipment, push power on-off switch on. 
  c. set the function indicator position to FREQ A and Gate time indicator   
to 1 Sec position. 
CAUTION 
1. APPLICATION OF INPUT VOLTAGES HIGHER THAN THE LIMITS LISTED 
IN THE SPECIFICATIONS SECTION MAY DAMAGE THE COUNTER. BEFORE 
APPLYING ANY SIGNAL TO THE INPUTS, MAKE CERTAIN THAT IT DOES 
NOT EXCEED THESE SPECIFIED MAXIMUMS. 
2. FREQUENCY COUNTER GROUND POINTS ARE CONNECTED DIRECTLY 
TO EARTH GROUND. ALWAYS CONNECT FREQUENCY COUNTER 
GROUND ONLY TO GROUND POINTS IN THE CIRCUIT UNDER TEST. 
3-3. Frequency Measurements 
3-3-1    INPUT A, B (0.1 Hz  100 MHz) 
a. Apply the signal to be measured to the input A and/or B BNC. 
b. Set the FREQ. A and/or B of function switch. 
c. Select the degree of resolution desired, using the gate time   
  selector switch.    
d. Frequency is given by the display. The gate indicator lights while each   
  measurement in progress, and the display is updated at the end of 
each measurement interval. 
  e. Engaging the hold switch “freezes” the display at the existing reading, 
  When hold is released, the display is updated and resumes counting. 
f. If necessary, engage the attenuator switch. When set to x 10 
(pushed in), this switch attenuates the input A and/or B signal by a 
factor of approximately 10 before application to the counter. This helps 
prevent miscounting caused by noisy or improperly terminated high 
amplitude signals. 
g. If necessary, engage the LPF (low pass filter) switch This route the 
input A and/or B through a low pass filter (-3 dB point of approximately 
100 KHz) before application to the frequency counter. This helps 
eliminate counting errors in low frequency measurements by minimizing 
effects of high frequency noise present on the input.           
h. When measurement the lower cut-off frequency (10 Hz), pushed in 










