Internal chirp generator with time aligned acquisition in a mixed-domain oscilloscope

Patent metadata

Field	Value
Publication number	US-9304148-B2
Application number	US-201213658563-A
Country	US
Kind code	B2
Filing date	Oct 23, 2012
Priority date	Oct 23, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A mixed-domain oscilloscope (MDO) includes a signal generator configured to generate a test signal having a span ranging from a user-configurable start frequency to a user configurable stop frequency, an output channel coupled to the signal generator and configured to transmit the test signal, an RF input channel configured to receive a return signal based on the test signal, an acquisition section configured to acquire and digitize the return signal as an acquisition record, and a ramp busy signal generator configured to substantially time-align the acquisition record with the test signal. The test signal includes a chirp signal that is a linearly swept sine wave that spans between the user-configurable start frequency and the user-configurable stop frequency. Methods include calibrating the chirp signal, connecting the MDO in various test configurations relative to external return loss bridge and DUT equipment, and performing measurements such as S21 (db), S11 (db), and distance-to-fault type measurements.

First claim

What is claimed is:

1. A mixed-domain oscilloscope, comprising:
a signal generator configured to generate a test signal having a span ranging from a user-configurable start frequency to a user configurable stop frequency;
an output channel coupled to the signal generator and configured to transmit the test signal;
an RF input channel configured to receive a return signal based on the test signal;
an acquisition section configured to acquire and digitize the return signal as an acquisition record; and
a ramp busy signal generator configured to substantially time-align the acquisition record with the test signal; wherein:
the test signal is a chirp signal;
the signal generator is configured to generate the chirp signal;
the return signal received by the RF input channel is based on the chirp signal; and
the acquisition section is configured to acquire, in a single acquisition, substantially the entire chirp signal; and
wherein the chirp signal is a linearly swept sine wave configured to span between the user-configurable start frequency and the user-configurable stop frequency.

2. The mixed-domain oscilloscope of claim 1 , wherein the test signal is a continuous wave signal.

3. The mixed-domain oscilloscope of claim 1 , wherein:
the ramp busy signal generator is configured to generate a ramp busy signal; and
the signal generator is configured to transmit the test signal responsive to the ramp busy signal.

4. A mixed-domain oscilloscope, comprising:
a signal generator configured to generate a test signal having a span ranging from a user-configurable start frequency to a user configurable stop frequency;
an output channel coupled to the signal generator and configured to transmit the test signal;
an RF input channel configured to receive a return signal based on the test signal;
an acquisition section configured to acquire and digitize the return signal as an acquisition record; and
a ramp busy signal generator configured to substantially time-align the acquisition record with the test signal; wherein:
the signal generator is configured to generate the chirp signal;
the return signal received by the RF input channel is based on the chirp signal; and
the acquisition section is configured to acquire, in a single acquisition, substantially the entire chirp signal; and
wherein a length of the acquisition record corresponds to the span of the chirp signal less a first margin at a beginning of the chirp signal and less a second margin at an ending of the chirp signal.

5. The mixed-domain oscilloscope of claim 4 , wherein:
the first margin is defined by a difference between a first edge of a ramp busy signal and the beginning of the acquisition record; and
the second margin is defined by a difference between a second edge of the ramp busy signal and the ending of the acquisition record.

6. A mixed-domain oscilloscope, comprising:
a signal generator configured to generate a test signal having a span ranging from a user-configurable start frequency to a user configurable stop frequency;
an output channel coupled to the signal generator and configured to transmit the test signal;
an RF input channel configured to receive a return signal based on the test signal;
an acquisition section configured to acquire and digitize the return signal as an acquisition record; and
a ramp busy signal generator configured to substantially time-align the acquisition record with the test signal;
wherein the acquisition section further comprises:
an analog-to-digital converter configured to digitize the return signal;
a block down converter coupled to the analog-to-digital converter and to the RF input channel, the block down converter being configured to receive the return signal from the RF input channel and to block feed the return signal to the analog-to-digital converter;
acquisition memory coupled to the analog-to-digital converter and configured to store the digitized signal as the acquisition record;
a digital down converter coupled to the acquisition memory and configured to digitally down-convert the digitized signal to a frequency span ranging from the user-configurable start frequency to the user-configurable stop frequency.

7. The mixed-domain oscilloscope of claim 6 , wherein:
the digital down converter includes a Discrete Fourier transform section configured to convert the digitized signal to the frequency domain; and
the mixed-domain oscilloscope further comprises a display configured to display a spectrum of the return signal so as to provide a measurement of a 2 port scalar s parameter.

8. The mixed-domain oscilloscope of claim 6 , wherein:
the test signal is a chirp signal;
the signal generator is configured to generate the chirp signal; and
the user-configurable start frequency corresponds to a beginning frequency of the chirp signal and the user-configurable stop frequency corresponds to an ending frequency of the chirp signal.

9. The mixed-domain oscilloscope of claim 8 , wherein the chirp signal is a linearly swept sine wave configured to span between the user-configurable start frequency and the user-configurable stop frequency.

10. The mixed-domain oscilloscope of claim 6 , wherein the test signal is a continuous wave signal.

11. The mixed-domain oscilloscope of claim 6 , wherein:
the ramp busy signal generator is configured to generate a ramp busy signal; and
the signal generator is configured to transmit the test signal responsive to the ramp busy signal.

12. A system for making measurements on a mixed-domain oscilloscope, the system comprising:
a device under test including first and second ports;
a mixed-domain oscilloscope including an output channel coupled to the first port of the device under test and an RF input channel coupled to the second port of the device under test, wherein the mixed-domain oscilloscope further includes:
a signal generator configured to generate a test signal having a span ranging from a user-configurable start frequency to a user configurable stop frequency;
an output channel coupled to the signal generator and configured to transmit the test signal to the first port of the device under test;
an RF input channel configured to receive a return signal from the second port of the device under test, the return signal being based on the test signal;
an acquisition section configured to acquire and digitize the return signal as an acquisition record; and
a ramp busy signal generator configured to substantially time-align the acquisition record with the test signal.

13. The system of claim 12 , wherein:
the test signal is a chirp signal;
the signal generator is configured to generate the chirp signal;
the return signal received by the RF input channel is based on the chirp signal; and
the acquisition section is configured to acquire, in a single acquisition, substantially the entire chirp signal.

14. The system of claim 13 , wherein the chirp signal is a linearly swept sine wave configured to span between the user-configurable start frequency and the user-configurable stop frequency.

15. The mixed-domain oscilloscope of claim 12 , wherein:
the ramp busy signal generator is configured to generate a ramp busy signal; and
the signal generator is configured to transmit the test signal responsive to the ramp busy signal.

Assignees

• Tektronix Inc

Inventors

• Dalebroux Donald J

Classifications

• G01R31/2837 Primary

  Characterising or performance testing, e.g. of frequency response (transient response G01R27/28) · CPC title

• G01R27/04

  in circuits having distributed constants {, e.g. having very long conductors or involving high frequencies} · CPC title

• G01R13/0236 Primary

  for presentation of more than one variable · CPC title

• G01R27/28

  Measuring attenuation, gain, phase shift or derived characteristics of electric four pole networks, i.e. two-port networks; Measuring transient response (in line transmission systems H04B3/46) · CPC title

• G01R13/0245 Primary

  for inserting reference markers · CPC title