To Test Bandwidth; Equivalent Time Test - Agilent Technologies 54845B Manual

Table of Contents

To test bandwidth

This test checks the bandwidth of the oscilloscope. The Agilent 54845B bandwidth at 1.5 GHz

and the Agilent 54846B bandwidth at 2.25 GHz oscilloscopes are checked using aliasing since

the trigger specification of these oscilloscopes is 1 GHz. The 1.5 GHz or the 2.25 GHz signal is

viewed with a time/division setting of approximately 50 µs/div where the on-screen display is an

untriggered sinewave that appears to be at a lower frequency, however the vertical response of

the amplifiers is correct.

Specification

Equivalent Time:

50Ω: 2.25 GHz (Agilent 54846B), 1.5 GHz (Agilent 54845B), 1 MΩ: 500 MHz (with Agilent

1161A probe)

Real Time:

50Ω: for Agilent 54846B — 2.25 GHz (2-channel mode), 1.0 GHz (4-channel mode)

50Ω: for Agilent 54845B — 1.5 GHz (2-channel mode), 1.0 GHz (4-channel mode)

1 MΩ: 500 MHz (with Agilent 1161A probe)

Equipment Required

Equipment

Critical Specifications

10—2250 MHz at ≈200 mVrms

Signal Generator

1—1.5 GHz ±3% accuracy

Power Meter/Sensor

Power Splitter

outputs differ by <0.15 dB

Cable

Type N (m) 24 inch

Termination

50Ω, BNC Connectors

Adapter

Type N (m) to BNC (m)

Probe

No Substitute

Probe Tip Adapter

1160 Series to BNC

Equivalent Time Test

Connect the equipment.

a With the N cable, connect the signal generator to the power splitter input. Connect the

power sensor to one output of the power splitter.

b With an N-to-BNC adapter, connect the other splitter output to the channel 1 input.

Press Default Setup to set the oscilloscope to default conditions.

Select Acquisition from the Setup menu. Select Equivalent Time sampling mode. Click

Close. Select Display from the Setup Menu. Unselect Connect Dots mode. Click Close.

Set the vertical scale for Channel 1 to 100 mV/div using the knob. Select 50Ω input

impedance.

Set the sweep speed to 50 ns/div using the horizontal sweep speed knob.

Set the signal generator for 10 MHz at +5.0 dBm.

The signal on the oscilloscope screen should be about five cycles at six divisions amplitude.

Bandwidth Check Limits

Do not exceed 6 divisions when making the bandwidth check.

Chapter 3: Testing Performance