Signal Simulation Request
Thought for 50 sec
Below is a starter SPICE net-list that exercises the audio path from the electret microphone input at MK1 to the switch node at SW2.
It intentionally:
It intentionally:
- Models only the blocks that form a continuous signal chain between the two points (MIC → MAX9814 pre-amp → two op-amp gain stages → output switch).
- Uses vendor-supplied macromodels where available (MAX9814) and generic ideal op-amp models for the three ADA4807 stages (replace with proper macro-models if you have them).
- Applies an AC-sweep stimulus so you can view frequency response, plus a quick transient test to see waveform shape at one representative frequency (1 kHz).
How to run it in Flux with CopilotSpice
* === Bone Conduction Hearing Aid v2.1 – Simplified Audio Path === * Units: V, A, seconds, Farads, Ohms, Henry *--------------------------------------------------------------- * 1) AC source (simulates acoustic pressure on electret element) VIN N_MICIN_GND 0 AC 1 SIN 0 1 1k * 2) Electret bias resistor (R3 2.2 k nominal) RBiasMic N_MICBIAS N_MICIN_GND 2200 * 3) MAX9814 pre-amp (IC4) * Download “MAX9814.SUB” from Maxim → File must be in same dir. XMAX9814 N_MICIN_GND N_MICBIAS N_MICOUT N_MAXVDD N_MAXGND MAX9814 * 4) Coupling capacitor C1 (1 µF) Ccouple1 N_MICOUT N_OP1_IN 1u * 5) 1st op-amp stage – [U1](https://www.flux.ai/:handle/:documentSlug?fit=U1) * Non-inverting gain set by R11 and R1/1 R11 N_OP1_IN N_OP1_OUT 100k Rfb1 N_OP1_OUT N_OP1_FB 10k EOP1 N_OP1_OUT 0 N_OP1_IN N_OP1_FB 999k * 6) Coupling / EQ network (C2/1 etc.) – simplified as single cap Ccouple2 N_OP1_OUT N_OP2_IN 470n * 7) 2nd op-amp stage – [U2](https://www.flux.ai/:handle/:documentSlug?fit=U2) EOP2 N_OP2_OUT 0 N_OP2_IN 0 400k Rload2 N_OP2_OUT 0 100k * 8) 3rd op-amp stage – [U3](https://www.flux.ai/:handle/:documentSlug?fit=U3) EOP3 N_OP3_OUT 0 N_OP2_OUT 0 200k Rload3 N_OP3_OUT 0 10k * 9) Output coupling cap to headphone jack / SW2 Ccouple3 N_OP3_OUT N_SW2 4.7u *—- Power rails (5 V and 2.5 V virtual rails) ——* V5 N_MAXVDD 0 5 V25 N_V25 0 2.5 *—- Ground references ——* .PARAM ac_in=1 *--------------------------------------------------------------- * AC frequency sweep 20 Hz → 20 kHz, 20 pts/dec .AC DEC 20 20 20000 .PROBE V(N_SW2) .PROBE V(N_MICIN_GND) *--------------------------------------------------------------- * Transient check: 1 ms to 10 ms at 1 kHz .TRAN 0.01m 10m .PROBE V(N_SW2) V(N_MICIN_GND) *--------------------------------------------------------------- .END
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Place the
MAX9814.SUBfile (or any other macro-models you add) in the same directory as your project’s exported net-list. -
Copy the entire block above into the chat after the
@simulatorkeyword, for example:
@simulator
<paste-the-netlist-above>
-
Copilot will parse the net-list and launch the Ngspice engine.
- The AC analysis returns a Bode plot of magnitude & phase from MK1 to SW2.
- The TRAN analysis provides the actual waveform at SW2 for a 1 kHz tone.
-
If Ngspice reports missing models:
- Replace
EOPxideal op-amps with real ADA4807 macromodels once you obtain them. - Verify every passive in the list exists (capacitance & resistance values).
- Replace
-
Rerun
@simulatorafter model fixes; Copilot will display the plots and let you download raw CSV data for further processing.
Feel free to tweak component values (e.g. gain-set resistors, coupling caps) or analysis settings (different frequency spans, input amplitudes) and re-run to examine performance.
Run AC sweep
Add noise analysis
Import op-amp models
Sweep feedback gain
Import SPICE netlist
