8

MEASURING RATE

FUNCTION

TIMES/SECOND

ACV

7

ACV + dB

7

DCV

7

AC + DC V

2

W

/nS

14

Diode

14

Capacitance

4 (< 100 µF)

DCI

7

ACI

7

AC + DC I

2

Temperature

6

Frequency

1 (>10 Hz)

Duty cycle/Pulse width

0.5 (>10 Hz)

DECIBEL (dB) CALCULATION

dB BASE

REFERENCE

DEFAULT REFERENCE

1 mW (dBm)

1-9999 W

50 W

1 V (dBV)

1 V

1 V

MANUAL AND INTERVAL DATA LOGGING

LOGGING

TYPE

U1251A

U1252A

U1253A

MANUAL

100

100

100

INTERVAL

200

200

1000

[1] All frequency counters are susceptible to errors. Shielding inputs from external noise pickup is critical to minimize measurement errors. For non-square wave signals,

add 5 counts.

[2] Output impedance: 3.5 kW maximum.

[3] The positive or negative pulse width must be greater than 50 µs for adjustment of the duty cycle or pulse width under different frequencies. Otherwise, the accuracy

and range will be different from the specifications defined.

[4] For signal frequencies greater than 1 kHz, an addition of 0.1% per kHz is added to the accuracy.

[5] For data logging to PC, maximum number of data points is dependent on available hard disk space.

[6] For the U1253A/U1253B model.

[1] For 5 V to 1000 V range, the specified input impedance in parallel with 10 MW at dual display.

[2] The specified input impedance (nominal) in parallel with <100 pF.

Table A

INPUT IMPEDANCE

FUNCTION

RANGE

INPUT IMPEDANCE

50.000 mV

10.00 MW

500.00 mV

10.00 MW

1000.0 mV

10.00 MW

5.0000 V

11.10 MW

50.000 V

10.10 MW

500.00 V

10.01 MW

1000.0 V

10.001 MW

50.000 mV

10.00 MW

500.00 mV

10.00 MW

1000.0 mV

10.00 MW

5.0000 V

10.00 MW

50.000 V

10.00 MW

500.00 V

10.00 MW

1000.0 V

10.00 MW

50.000 mV

10.00 MW

500.00 mV

10.00 MW

1000.0 mV

10.00 MW

5.0000 V

11.10 MW || 10 MW

50.000 V

10.10 MW || 10 MW

500.00 V

10.01 MW || 10 MW

1000.0 V

10.001 MW || 10 MW