TDFS | PartQuest™ Explore

Switched-Capacitor Filter Frequency Response using TDFS

Mike Donnelly
Designer19

Mike Donnelly

Member for

10 years 5 months

1,540

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Copy of Laser Temperature Regulator TDFS - on Fri, 01/05/2024 - 07:44

mark_arsenault
Designer244467

mark_arsenault

Member for

1 year 5 months

209

designs

4

groups

Member of the PartQuest Explore development team.

Copy of Laser Temperature Regulator TDFS - on Fri, 01/05/2024 - 07:42

mark_arsenault
Designer244467

mark_arsenault

Member for

1 year 5 months

209

designs

4

groups

Member of the PartQuest Explore development team.

low pass filter

User-1692310955
Designer248683

User-1692310955

Member for

8 months

13

designs

1

groups

Welcome to the community!!

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

PBAJA

abigail.nino
Designer244076

abigail.nino

Member for

1 year 8 months

19

designs

1

groups

I'm a member of the PartQuest Explore community.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Copy of Switched-Capacitor Filter Frequency Response using TDFS - on Fri, 11/17/2023 - 20:36

User-1692310955
Designer248683

User-1692310955

Member for

8 months

13

designs

1

groups

Welcome to the community!!

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Copy of Switched-Capacitor Filter Frequency Response using TDFS - on Mon, 07/17/2023 - 21:44

RobertSt-Laurent
Designer172066

RobertSt-Laurent

Member for

6 years 3 months

1

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Stage testing of Switched-Capacitor Filter Frequency Response using TDFS

Mike Donnelly
Designer19

Mike Donnelly

Member for

10 years 5 months

1,540

designs

10

groups

Member of the PartQuest Explore Development Team. Focused on modeling and simulation of analog, mixed-signal and multi-discipline systems covering a broad range of applications, including power electronics, controls and mechatronic systems.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Copy of New TDFS - on Tue, 03/09/2021 - 13:36

bedrosian1134
Designer198997

bedrosian1134

Member for

5 years 10 months

58

designs

4

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

To see the actual frequency sweep results from the TDFS analysis, open the full waveform viewer and expand the folder "Switched-Capacitor Filter Frequency Response using TDFS -&gt; Swept Frequency Gain Measure". The waveform "v1_over_vosc_complex -&gt; dbMag" is the magnitude of the frequency response of the R-C filter, and "v2_over_vosc_complex -&gt; dbMag" is the magnitude of the frequency response of the switched capacitor filter, both expressed in dB. Note that the phase response waveforms are also available.

For reference, note in the schematic that the R-C filter is connected to the channel 1 input of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Copy of Switched-Capacitor Filter Frequency Response using TDFS - on Sun, 12/20/2020 - 02:17

vijay1607130725
Designer237013

vijay1607130725

Member for

3 years 4 months

2

designs

1

groups

Add a bio to your profile to share information about yourself with other SystemVision users.

Description

This design shows the use of the TDFS (Time Domain Frequency Sweep) method to measure the frequency response of two low-pass filters. One is just a simple RC filter circuit with 1 kHz cut-off frequency. The other is an equivalent filter using a switched-capacitor implementation.

Both small-signal AC (frequency domain) and TDFS (time-domain) analyses are run, and both give the same results for the RC filter. However, because of the switching aspect of the switched-capacitor filter, the results of the AC analysis are meaningless for that circuit. However, the TDFS approach is valid for that filter also, as well as for any other circuit or system containing switching, sampled data or digital content.

For reference, note in the schematic that the R-C filter is connected to channel 1 of the TDFS instrument, and the switched capacitor filter is connected to channel 2, hence the v1 and v2 distinction in the name of the results for the magnitude (dbMag) and phase. Both are measured relative to the stimulus input vosc, the oscillator output.

About text formats

Terms of Use Cookie Notice Data Privacy Notice

Mike DonnellyDesigner19

Member for

mark_arsenaultDesigner244467

Member for

mark_arsenaultDesigner244467

Member for

User-1692310955Designer248683

Member for

abigail.ninoDesigner244076

Member for

User-1692310955Designer248683

Member for

RobertSt-LaurentDesigner172066

Member for

Mike DonnellyDesigner19

Member for

bedrosian1134Designer198997

Member for

vijay1607130725Designer237013

Member for

Mike Donnelly
Designer19

mark_arsenault
Designer244467

mark_arsenault
Designer244467

User-1692310955
Designer248683

abigail.nino
Designer244076

User-1692310955
Designer248683

RobertSt-Laurent
Designer172066

Mike Donnelly
Designer19

bedrosian1134
Designer198997

vijay1607130725
Designer237013