AIDT 온디바이스 STEM 방사광 X선 극저온 키네틱 인덕턴스 진행파 파라메트릭 증폭기(KITWPA) 서보 제어기

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.CryoKitwpaAmplifier
{
    /// <summary>
    /// KITWPA 증폭 이득 및 펌프 텔레메트리 상태
    /// </summary>
    public readonly ref struct KitwpaTelemetryState
    {
        public readonly double SignalGainDb;              // 신호 대역(6GHz) 측정 이득 [dB]
        public readonly double GainRippleDb;              // 대역폭 내 리플 편차 [dB]
        public readonly double CryoStageTempKelvin;       // 냉각단 헬륨 온도 [K]
        public readonly double PumpFrequencyGigaHz;       // 현재 펌프 주파수 [GHz]

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public KitwpaTelemetryState(double gain, double ripple, double tempK, double fPump)
        {
            SignalGainDb = gain;
            GainRippleDb = ripple;
            CryoStageTempKelvin = tempK;
            PumpFrequencyGigaHz = fPump;
        }
    }

    /// <summary>
    /// KITWPA 펌프 전력 및 DC 바이어스 서보 지령
    /// </summary>
    public readonly ref struct KitwpaServoCommand
    {
        public readonly double CommandedPumpPowerDbm;     // 펌프 마이크로파 파워 [dBm]
        public readonly double CommandedDcBiasMilliAmps;  // 3WM/4WM 위상 매칭 DC 바이어스 [mA]
        public readonly bool QuantumGainLocked;           // 20dB 양자 이득 안정 잠금

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public KitwpaServoCommand(double pDbm, double iDc, bool locked)
        {
            CommandedPumpPowerDbm = pDbm;
            CommandedDcBiasMilliAmps = iDc;
            QuantumGainLocked = locked;
        }
    }

    /// <summary>
    /// 10,000Hz 0-Alloc 극저온 KITWPA 서보 엔진
    /// </summary>
    public sealed class CryoKitwpaServoEngine
    {
        private const double TargetGainDb = 20.0;         // 목표 이득 20.0 dB
        private const double MaxPumpDbm = -5.0;           // 최대 펌프 파워 한계
        private double _intGainErr;
        private double _currentPumpDbm;
        private double _currentDcBiasMa;

        public CryoKitwpaServoEngine()
        {
            _intGainErr = 0.0;
            _currentPumpDbm = -18.0;
            _currentDcBiasMa = 1.2;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public KitwpaServoCommand UpdateServoLoop(in KitwpaTelemetryState telemetry, double dtSeconds)
        {
            // 1. 이득 오차 계산
            double gainErr = TargetGainDb - telemetry.SignalGainDb;
            _intGainErr = Math.Clamp(_intGainErr + (gainErr * dtSeconds), -20.0, 20.0);

            // 2. 펌프 파워 제어 (PI 서보)
            double deltaPump = (gainErr * 0.4) + (_intGainErr * 0.8);
            _currentPumpDbm = Math.Clamp(_currentPumpDbm + (deltaPump * dtSeconds), -30.0, MaxPumpDbm);

            // 3. 리플 억제형 DC 바이어스 전류 튜닝 (Dispersion Fine-Tuning)
            if (telemetry.GainRippleDb > 1.5)
            {
                _currentDcBiasMa += 0.05 * dtSeconds; // 미세 튜닝
            }
            else if (telemetry.GainRippleDb < 0.5 && _currentDcBiasMa > 1.0)
            {
                _currentDcBiasMa -= 0.02 * dtSeconds;
            }
            _currentDcBiasMa = Math.Clamp(_currentDcBiasMa, 0.0, 4.0);

            bool isLocked = (Math.Abs(gainErr) < 0.3 && telemetry.GainRippleDb < 1.0);
            return new KitwpaServoCommand(_currentPumpDbm, _currentDcBiasMa, isLocked);
        }
    }
}