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Лабораторная 10.4 — KiCad schematic mini-project

Цель

Подготовить мини-проект схемы для SDR-стенда: аттенюатор/фильтр, BOM, ограничения и safety checklist.

Что выполняется

В работе студент:

  1. выбирает назначение вспомогательной схемы;
  2. рассчитывает attenuation/filter параметры;
  3. оформляет schematic concept;
  4. составляет BOM;
  5. фиксирует ограничения и safety notes.

Результат

После выполнения работы должны быть получены:

  • schematic concept;
  • BOM table;
  • расчёт параметров;
  • safety checklist;
  • вывод о пригодности схемы для SDR bench.

Подробная техническая часть

Lab 10.4 — KiCad Schematic Mini-Project

Goal

Prepare a small reproducible electronics mini-project for the SDR bench: an RF-safe attenuator/filter interface documented as a schematic, BOM and safety checklist.

Engineering question

Can another engineer reproduce the front-end helper circuit and understand its limits before connecting it to SDR hardware?

Mini-project concept

flowchart LR
    IN[Signal input] --> ATT[Attenuator / divider]
    ATT --> FILT[Optional RC filter]
    FILT --> OUT[SDR input / measurement node]
    OUT --> LOAD[Load / receiver impedance]

Required schematic blocks

Block Purpose
Input connector defines signal entry point
Attenuator reduces level before receiver
Optional RC filter limits low-frequency or high-frequency components
Output connector connects to SDR or measurement input
Ground reference avoids ambiguous return path
Notes documents impedance and safety limits

BOM template

Ref Value Package Purpose Notes
R1 9 kOhm THT/SMD divider upper resistor educational example
R2 1 kOhm THT/SMD divider lower resistor gives about -20 dB unloaded
C1 100 nF THT/SMD optional RC capacitor choose by target cutoff
J1 connector SMA/BNC/header input depends on bench
J2 connector SMA/BNC/header output depends on receiver

KiCad deliverables

A complete mini-project should include:

kicad/
  sdr_frontend_helper.kicad_pro
  sdr_frontend_helper.kicad_sch
  bom.csv
  README.md

If KiCad is not available, document the schematic in Markdown first and convert it to KiCad later.

Safety checklist

  • [ ] Maximum input level is stated.
  • [ ] Expected attenuation is calculated.
  • [ ] Load impedance assumption is written.
  • [ ] DC coupling/AC coupling is documented.
  • [ ] SDR input protection is considered.
  • [ ] Circuit is tested at low level first.
  • [ ] Measurement metadata mention the interface circuit.

Report checklist

  • [ ] Include schematic or clear diagram.
  • [ ] Include BOM.
  • [ ] Include attenuation calculation.
  • [ ] Include RC cutoff calculation if filter is used.
  • [ ] Explain limitations of the circuit.
  • [ ] State whether it is safe for the intended SDR experiment.

Engineering conclusion template

The KiCad mini-project implements ______ with expected attenuation ____ dB and optional cutoff ____ Hz.
It is suitable / not suitable for the SDR bench because ______. The key limitation is ______.