Band overlay separator

Patent metadata

Field	Value
Publication number	US-9933458-B2
Application number	US-201514674344-A
Country	US
Kind code	B2
Filing date	Mar 31, 2015
Priority date	Mar 31, 2015
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

A test and measurement instrument including a splitter configured to split an input signal into at least two split signals, at least two harmonic mixers configured to mix an associated split signal with an associated harmonic signal to generate an associated mixed signal, at least two digitizers configured to digitize the associated mixed signal, at least two MIMO polyphase filter arrays configured to filter the associated digitized mixed signal of an associated digitizer of the at least two digitizers, at least two pairs of band separation filters configured to receive the associated digitized mixed signals from each of the MIMO polyphase filter arrays and output a low band of the input signal and a high band of the input signal based on a time different between the at least two digitizers and a phase drift of a local oscillator, and a combiner configured to combine the low band of the input signal and the high band of the input signal to form a reconstructed input signal.

First claim

The invention claimed is:

1. A test and measurement instrument, comprising:
a splitter configured to split an input signal into at least two split signals, each split signal including substantially the entire bandwidth of the input signal;
at least two harmonic mixers, each harmonic mixer configured to mix an associated split signal of the at least two split signals with an associated harmonic signal to generate an associated mixed signal;
at least two digitizers, each digitizer configured to digitize the associated mixed signal of an associated harmonic mixer of the at least two harmonic mixers;
at least two multiple input multiple output (MIMO) polyphase filter arrays, each MIMO polyphase filter array configured to filter the associated digitized mixed signal of an associated digitizer of the at least two digitizers;
at least two pairs of band separation filters configured to receive the associated digitized mixed signals from each of the multiple input multiple output polyphase filter arrays and to separate and output a low band of the input signal and a high band of the input signal based on a time difference between the at least two digitizers and a phase drift of a local oscillator; and
a combiner configured to combine the low band of the input signal and the high band of the input signal to form a reconstructed input signal.

2. The test and measurement instrument of claim 1 , wherein each MIMO polyphase filter array is an 8×8 MIMO polyphase filter array.

3. The test and measurement instrument of claim 1 , further comprising a bandwidth enhance filter configured to filter the reconstructed input signal.

4. The test and measurement instrument of claim 1 , further comprising:
a first summer associated with a first group of the at least two pairs of band separation filters configured to output the low band of the input signal, the first summer configured to combine the outputs of each of the first group of the at least two pairs of band separation filters to form the low band of the input signal; and
a second summer associated with a second group of the at least two pairs of band separation filters configured to output the high band of the input signal, the second summer configured to combine the outputs of each of the second group of the at least two pairs of band separation filters to form the high band of the input signal.

5. The test and measurement instrument of claim 4 , wherein the high band output from the at least two pairs of band separation filters is an aliased high band, the test and measurement instrument further comprising a high band multiplier configured to multiple the aliased high band by a signal to convert the aliased high band to a non-aliased high band, wherein the combiner combines the low band and the non-aliased high band to form the reconstructed input signal.

6. The test and measurement instrument of claim 5 , further comprising an interpolator configured to interpolate each of the low band and the aliased high-band prior to multiplying the aliased high band by the signal to convert the aliased high band to the non-aliased high band.

7. The test and measurement instrument of claim 1 , further comprising a filter computation unit configured to compute filter coefficients for each of the at least two pairs of band separation filters.

8. A method, comprising:
splitting an input signal into at least two split signals, each split signal including substantially the entire bandwidth of the input signal;
mixing each split signal with an associated harmonic signal to generate an associated mixed signal;
digitizing each of the associated mixed signals;
filtering each digitized mixed signal through an associated multiple input multiple output (MIMO) polyphase filter array;
filtering by at least two pairs of band separation filters the digitized mixed signal from each of the MIMO polyphase filter array based on a time difference between the at least two digitizers and a phase drift of a local oscillator;
outputting from the at least two pairs of band separation filters a low band of the input signal and a high band of the input signal; and
combining the low band of the input signal and the high band of the input signal to form a reconstructed input signal.

9. The method of claim 8 , wherein each MIMO polyphase filter array is an 8×8 MIMO polyphase filter array.

10. The method of claim 8 , further comprising filtering the reconstructed input signal through a bandwidth enhance filter.

11. The method of claim 8 , further comprising:
combining the outputs of each of a first group of the at least two pairs of band separation filters configured to output the low band of the input signal to form the reconstructed low band of the input signal; and
combining the outputs of each of a second group of the at least two pairs of band separation filters configured to output the high band of the input signal to form the reconstructed high band of the input signal.

12. The method of claim 11 , wherein the reconstructed high band output from the combiner is an aliased high band, the method further comprising multiplying the aliased reconstructed high band by a signal to convert the aliased reconstructed high band to a non-aliased reconstructed high band, wherein combining the low band of the input signal and the high band of the input signal to form a reconstructed input signal includes combining the reconstructed low band and the non-aliased reconstructed high band to form the reconstructed input signal.

13. The method of claim 12 , further comprising interpolating each of the reconstructed low band and the aliased reconstructed high-band prior to multiplying the aliased reconstructed high band by the signal to convert the aliased reconstructed high band to the non-aliased reconstructed high band.

14. The method of claim 8 , further comprising computing filter coefficients for each of the at least two pairs of band separation filters.

Assignees

• Tektronix Inc

Inventors

• Pickerd John J
• Tan Kan

Classifications

• G01R13/0272 Primary

  for sampling · CPC title

• G01R13/0218 Primary

  Circuits therefor · CPC title

• H03M1/1052

  using two or more look-up tables each corresponding to a different type of error, e.g. for offset, gain error and non-linearity error respectively · CPC title

• G01R13/225

  particularly adapted for storage oscilloscopes · CPC title

• H03M1/1215

  using time-division multiplexing · CPC title