G E N E R A L The FC-757 is a universal counter. It can be used to — T i m e measurement function measure frequencies (175MHz M a x . ) , period, frequency The time measurement function...
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S P E C I F I C A T O N S x 1 , x 1 0 , x 1 0 0 , X1000 M a g n i f i c a t i o n [Frequency Measurement (Channel A ) ] ( G a t e time) [Frequency Ratio Measurement ( A / B ) ]...
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Single-shot pulse W a i t by reset A t t e n u a t i o n x 1 ( 1 / 1 ) , x 1 0 ( 1 x 1 0 ) processing L o w pass f i l t e r 10kHz, - 3 d B [Event input Total Measurement ( A ) ]...
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0.01s, 0.1s, 1.0s, 10s Counting time 3 x 1 0 - / 0 to 40 °C S t a b i l i z a t i o n 5 x 1 0 ' / m o n t h ( G a t e time) (Tenperature f a c t o r , aging rate)
PRECAUTIONS FOR USE T u r n off the product and then connect it w i t h T h i s counter can s t a r t its operation a t the A C w a l l outlet by using the accessory power moment when power is applied.
PANEL E X P L A N A T I O N interval is being measured. T h i s L E D indicator 4 - 1 F r o n t panel becomes inactive when the frequency r a t i o meas- ®...
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• T h i s switch is helpless in the frequency r a t i o range : measurement mode and event t o t a l count meas- 5Hz to 10MHz urement mode, Measurement s e n s i t i v i t y : ®...
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e. ' T O T A L / A (event input t o t a l count) mode R A T I O A / B (frequency r a t i o ) mode The T O T A L / A mode is an operational mode The R A T I O A / B mode is an operational mode...
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F o r the 220V or 240V-power requirement, use If this s w i t c h is set to the E X T . side, the the 0.125A/250V slow-blow type fuse. universal counter can be connected w i t h an When you replace the current fuse, refer external 1 0 - M H z time base clock generator v i a section 7-1 'Maintenance'...
4 - 3 Case surface The opening is normally covered w i t h a rubber ® There is an opening on the case surface. T h i s cap. If the T C X O needs to be fine adjusted, opening is provided for fine adjustment of please contact your dealer.
OPERATING PROCEDURES E v e r y time when you s t a r t using the FC-757 M u l t i - Select the F R E Q / A mode by using F U N C Functional universal counter, look a t the rear panel switch @ .
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attenuated into 1/10 before reaching the Trigger Level Adjustment counter. T h i s attenuates noise-superimposed The trigger level of the input signals to input signals. In addition, the attenuation C H A N N E L A input juck can be changed by circuit preprocesses a signal w i t h rather a T R I G L E V E L control...
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C H A N N E L A and C H A N N E L B are Symbol A - » B indicates t h a t the t r a n s i t i o n both provided w i t h the input adjustment time f r o m channel A to channel B is functions.
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on the Display is held a s it i s . If the s w i t c h is pressed ( jm-), t r a n s i t i o n If it is turned off, a new measurement cycle time w i l l be measured in milliseconds.
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. interval measurement mode and otherwise during a fixed certain period is measured. should be set as indicated in v a r i o u s m u l t i - T h i s measurement period can be set by using the f r o n t panel switch or the rear panel gate shot time interval measurement modes.
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® The T T L level of the input gate signal I N P U T S T A R T / S T O P juck, that i s , if the terminal , the T O T A L I Z E I N P U T S T A R T / S T O P juck is is left 'open', the count operation w i l l...
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event t o t a l count measurement mode. 5 - 6 Display Description If the F R E Q / A measurement mode 5 - 6 - 1 Display L a y o u t is selected w i t h F U N C switch ®...
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pseudo trigger signal may cause measure- order d i g i t s change very quickly, so t h a t ment error. T h i s measurement error can be becomes d i f f i c u l t to f o l l o w the display v a l - reduced by increasing the number of meas- ues w i t h eyesight.
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ment mode because higher precision d a t a into consideration because a new measure- can be displayed. If relatively high-frequen- ment operation w i l l s t a r t . cy signal is measured, the frequency meas- In the f o l l o w i n g paragraphs, the relation- urement...
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Frequency r a t i o mode A s the above table shows, the gate time The frequency r a t i o mode requires w i l l be short if a low resolution value is signals to be input to the counter input selected.
MEASURING CONSIDERATIONS Use of attenuator probe Interval between measurements The input impedance (1.2Megaohm, and 40pF or The interval between measurements ( G A T E less) of the C H A N N E L A input juck is not L E D O F F period) is fixed to 200 fected through manipulation...
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Use (+) slope for the C H A N N E L A selection on the Display is not updated u n t i l ! the new while ( - ) slope for the C H A N N E L B selection. measurement cycle is completed.
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6 - 5 Use of T R I G L E V E L control Relationship between period measurement mode T R I G L E V E L control ® is provided to adjust time interval mode the trigger levels of the input signals to It is strongly recommended t h a t the period meas- C H A N N E L A .
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Self check mode The self check mode is provided to check the G A T E L E D (D remains active during the internal general functions of the FC-757 universal interval period. The measurement interval frequency counter f o r a short t i m e .
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Seft open a f t e r the counter has entered the "88.8.8.8.8.8.8". A t the same t i m e , the self-check mode, and then v e r i f y t h a t the M H z / m s indication L E D and the O V E R F L O W output results agree to those listed below.
MAINTENANCE Change in power supply voltage C A U T I O N If a different-level power supply voltage needs to Be sure to disconnect the power cable f r o m the be applied to the product, use power supply socket, before conducting the following operation.
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A p r o d u c t K E N W O O D C O R P O R A T I O N 1 7-5, 2-chome, Shibuya, Shibuya-ku, Tokyo 150, Japan...