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CALCULATORS / CONTROL SYSTEMS AND DYNAMIC RESPONSE

Transfer-function frequency response calculator

Single-pole low-pass frequency response at one frequency.

controls-bode.napkin / editable
✓ checks pass

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenariomagnitudedecibelsphasedeg
1.693474.57553-32.1419
1.354772.63733-32.1419

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

gain target at test frequency1.69 ✓ passes

BASELINE INPUTS

CALCULATED

magnitude1.6935
decibels4.5755
phase-32.142 deg

Edits change the baseline source.

Calculated from your source · not saved
Baseline · Baseline
gain target at test frequency1.69 ✓ passes
alternative · alternative
gain target at test frequency1.35 ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

magnitude
magnitude = gain/sqrt(1+(2*pi*frequency*timeConstant)^2)
decibels
decibels = 20*log10(magnitude)
phase
phase = -atan(2*pi*frequency*timeConstant) [deg]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

gain
2
time constant
0.1 s
frequency
1 Hz

Calculated

magnitude
1.69347
decibels
4.57553
phase
-32.1419 deg

Assumptions and limits

Single-pole low-pass frequency response at one frequency.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Transfer-function frequency response. Inputs: poles; zeros; gain; frequency range. Outputs: Bode magnitude and phase. Model scope: Declared linear or low-order nonlinear plant models. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

  • Inputs: poles, zeros, gain, frequency range
  • Outputs: Bode magnitude and phase
  • Modes: calculate, compare, sweep
  • Drawing: Response and stability plots

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS

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