diff --git a/README.md b/README.md
index a9d0537..f172a8c 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,7 @@ PyQt6-приложение для управления лазерной плат
 
 - ручной режим: `T1/T2/I1/I2`
 - live telemetry: `T1/T2`, внешние термисторы, фотодиоды, `3V3/5V1/5V2/7V0`
+- TEC drive modulation: синусоидальная добавка к выходу TEC PID для выбранного лазера
 - AD9102: saw/SRAM режимы и загрузка custom waveform
 - AD9833, DS1809 и STM32 DAC через отдельные firmware-команды
 - сохранение профиля на SD-карту устройства
diff --git a/laser_control/constants.py b/laser_control/constants.py
index 650a77a..ba483d2 100644
--- a/laser_control/constants.py
+++ b/laser_control/constants.py
@@ -34,6 +34,7 @@ CMD_STM32_DAC_CONTROL = 0xBBBB
 CMD_AD9102_WAVE_CONTROL = 0xCCCC
 CMD_AD9102_WAVE_DATA = 0xDDDD
 CMD_PROFILE_SAVE_DATA = 0xEEEE
+CMD_TEC_MODULATION_CONTROL = 0xF0F0
 
 # ---- Setup-word bit layout from firmware app_decode_work_packet()
 
@@ -102,6 +103,9 @@ DS1809_FLAG_DECREMENT = 0x0002
 
 STM32_DAC_FLAG_ENABLE = 0x0001
 
+TEC_MODULATION_FLAG_ENABLE = 0x0001
+TEC_MODULATION_FLAG_CHANNEL_2 = 0x0002
+
 AD9102_WAVE_OPCODE_BEGIN = 0x0001
 AD9102_WAVE_OPCODE_COMMIT = 0x0002
 AD9102_WAVE_OPCODE_CANCEL = 0x0003
@@ -184,6 +188,11 @@ DS1809_PROFILE_POSITION_MAX = 63
 STM32_DAC_CODE_MIN = 0
 STM32_DAC_CODE_MAX = 4095
 
+TEC_MODULATION_FREQUENCY_MIN_HZ = 50
+TEC_MODULATION_FREQUENCY_MAX_HZ = 2_000
+TEC_MODULATION_AMPLITUDE_CODE_MIN = 0
+TEC_MODULATION_AMPLITUDE_CODE_MAX = 4_096
+
 # ---- Rail tolerances
 
 VOLT_3V3_MIN = 3.1
@@ -218,6 +227,8 @@ DEFAULT_STM32_DAC_VREF = 2.5
 DEFAULT_STM32_DAC_CODE = round(
     DEFAULT_STM32_DAC_VOLT / DEFAULT_STM32_DAC_VREF * STM32_DAC_CODE_MAX
 )
+DEFAULT_TEC_MODULATION_FREQUENCY_HZ = 1_000
+DEFAULT_TEC_MODULATION_AMPLITUDE_CODE = 256
 
 DEFAULT_PI_P = 2560
 DEFAULT_PI_I = 128
diff --git a/laser_control/controller.py b/laser_control/controller.py
index 6799eac..4b92bb7 100644
--- a/laser_control/controller.py
+++ b/laser_control/controller.py
@@ -50,6 +50,10 @@ from .constants import (
     STM32_DAC_CODE_MIN,
     STATUS_RESPONSE_LENGTH,
     WAIT_AFTER_SEND_SEC,
+    TEC_MODULATION_AMPLITUDE_CODE_MAX,
+    TEC_MODULATION_AMPLITUDE_CODE_MIN,
+    TEC_MODULATION_FREQUENCY_MAX_HZ,
+    TEC_MODULATION_FREQUENCY_MIN_HZ,
 )
 from .exceptions import (
     CommunicationError,
@@ -429,6 +433,44 @@ class LaserController:
         )
         logger.info("STM32 DAC configured: enabled=%s code=%d", enabled, dac_code)
 
+    def configure_tec_modulation(
+        self,
+        *,
+        enabled: bool,
+        laser: int,
+        frequency_hz: int,
+        amplitude_code: int,
+    ) -> None:
+        """Configure fast zero-mean TEC drive modulation around the PID output."""
+        laser = self._validate_int_range(laser, "laser", 1, 2)
+        frequency_hz = self._validate_int_range(
+            frequency_hz,
+            "frequency_hz",
+            TEC_MODULATION_FREQUENCY_MIN_HZ,
+            TEC_MODULATION_FREQUENCY_MAX_HZ,
+        )
+        amplitude_code = self._validate_int_range(
+            amplitude_code,
+            "amplitude_code",
+            TEC_MODULATION_AMPLITUDE_CODE_MIN,
+            TEC_MODULATION_AMPLITUDE_CODE_MAX,
+        )
+        self._send_and_expect_ok(
+            Protocol.encode_tec_modulation_control(
+                enabled=enabled,
+                laser=laser,
+                frequency_hz=frequency_hz,
+                amplitude_code=amplitude_code,
+            )
+        )
+        logger.info(
+            "TEC modulation configured: enabled=%s laser=%d frequency_hz=%d amplitude_code=%d",
+            enabled,
+            laser,
+            frequency_hz,
+            amplitude_code,
+        )
+
     def save_profile_to_sd(self, request: ProfileSaveRequest) -> None:
         """Stream a rendered profile INI and optional waveform CSV to the device SD card."""
         if not isinstance(request, ProfileSaveRequest):
diff --git a/laser_control/gui/sections.py b/laser_control/gui/sections.py
index 63f1235..6d7e428 100644
--- a/laser_control/gui/sections.py
+++ b/laser_control/gui/sections.py
@@ -51,6 +51,8 @@ from laser_control.constants import (
     DEFAULT_DS1809_PROFILE_POSITION,
     DEFAULT_DS1809_PULSE_MS,
     DEFAULT_STM32_DAC_CODE,
+    DEFAULT_TEC_MODULATION_AMPLITUDE_CODE,
+    DEFAULT_TEC_MODULATION_FREQUENCY_HZ,
     DEFAULT_TEMP1_C,
     DEFAULT_TEMP2_C,
     DS1809_COUNT_MAX,
@@ -64,6 +66,10 @@ from laser_control.constants import (
     AD9833_OUTPUT_FREQ_MIN_HZ,
     STM32_DAC_CODE_MAX,
     STM32_DAC_CODE_MIN,
+    TEC_MODULATION_AMPLITUDE_CODE_MAX,
+    TEC_MODULATION_AMPLITUDE_CODE_MIN,
+    TEC_MODULATION_FREQUENCY_MAX_HZ,
+    TEC_MODULATION_FREQUENCY_MIN_HZ,
     TEMP_MAX_C,
     TEMP_MIN_C,
 )
@@ -151,6 +157,7 @@ def build_device_group(owner) -> QGroupBox:
     tabs.addTab(_build_ad9102_tab(owner), "Генератор AD9102")
     tabs.addTab(_build_ad9833_tab(owner), "Генератор AD9833")
     tabs.addTab(_build_aux_tab(owner), "Выходы и DS1809")
+    tabs.addTab(_build_tec_modulation_tab(owner), "TEC модуляция")
     tabs.addTab(_build_wave_tab(owner), "Своя форма")
     layout.addWidget(tabs)
     return group
@@ -448,6 +455,54 @@ def _build_aux_tab(owner) -> QWidget:
     return tab
 
 
+def _build_tec_modulation_tab(owner) -> QWidget:
+    tab = QWidget()
+    layout = QFormLayout(tab)
+    layout.setHorizontalSpacing(12)
+    layout.setVerticalSpacing(8)
+
+    owner._tec_mod_enable = QCheckBox("Включить модуляцию")
+    owner._tec_mod_laser = QComboBox()
+    owner._tec_mod_laser.addItem("Лазер 1", 1)
+    owner._tec_mod_laser.addItem("Лазер 2", 2)
+    owner._tec_mod_frequency_hz = _int_spinbox(
+        TEC_MODULATION_FREQUENCY_MIN_HZ,
+        TEC_MODULATION_FREQUENCY_MAX_HZ,
+        DEFAULT_TEC_MODULATION_FREQUENCY_HZ,
+        suffix=" Гц",
+    )
+    owner._tec_mod_frequency_hz.setSingleStep(50)
+    owner._tec_mod_frequency_hz.setGroupSeparatorShown(True)
+    owner._tec_mod_amplitude_code = _int_spinbox(
+        TEC_MODULATION_AMPLITUDE_CODE_MIN,
+        TEC_MODULATION_AMPLITUDE_CODE_MAX,
+        DEFAULT_TEC_MODULATION_AMPLITUDE_CODE,
+    )
+    owner._tec_mod_amplitude_code.setSingleStep(16)
+    owner._tec_mod_amplitude_code.setGroupSeparatorShown(True)
+    owner._apply_tec_modulation_button = _expanding_button("Применить TEC модуляцию", primary=True)
+    owner._apply_tec_modulation_button.clicked.connect(owner._on_apply_tec_modulation)
+
+    layout.addRow(owner._tec_mod_enable)
+    layout.addRow("Лазер", owner._tec_mod_laser)
+    layout.addRow(
+        f"Частота ({TEC_MODULATION_FREQUENCY_MIN_HZ}..{TEC_MODULATION_FREQUENCY_MAX_HZ} Гц)",
+        owner._tec_mod_frequency_hz,
+    )
+    layout.addRow(
+        f"Амплитуда DAC ({TEC_MODULATION_AMPLITUDE_CODE_MIN}..{TEC_MODULATION_AMPLITUDE_CODE_MAX})",
+        owner._tec_mod_amplitude_code,
+    )
+    layout.addRow(owner._apply_tec_modulation_button)
+
+    owner._tec_mod_frequency_hz.setToolTip("Частота синусоидальной добавки к выходу TEC PID.")
+    owner._tec_mod_amplitude_code.setToolTip(
+        "Пиковая амплитуда добавки в кодах внешнего TEC DAC. "
+        "Прошивка ограничивает её по доступному запасу вокруг текущего PID-кода."
+    )
+    return tab
+
+
 def _build_wave_tab(owner) -> QWidget:
     tab = QWidget()
     layout = QVBoxLayout(tab)
diff --git a/laser_control/gui/window.py b/laser_control/gui/window.py
index 1d69639..117c193 100644
--- a/laser_control/gui/window.py
+++ b/laser_control/gui/window.py
@@ -66,6 +66,7 @@ class MainWindow(QMainWindow):
     request_apply_ad9833 = pyqtSignal(bool, bool, int)
     request_pulse_ds1809 = pyqtSignal(bool, int, int)
     request_set_stm32_dac = pyqtSignal(bool, int)
+    request_apply_tec_modulation = pyqtSignal(bool, int, int, int)
     request_upload_wave = pyqtSignal(object)
     request_cancel_wave = pyqtSignal()
     request_save_profile = pyqtSignal(object)
@@ -219,6 +220,7 @@ class MainWindow(QMainWindow):
         self.request_apply_ad9833.connect(self._worker.apply_ad9833)
         self.request_pulse_ds1809.connect(self._worker.pulse_ds1809)
         self.request_set_stm32_dac.connect(self._worker.set_stm32_dac)
+        self.request_apply_tec_modulation.connect(self._worker.apply_tec_modulation)
         self.request_upload_wave.connect(self._worker.upload_ad9102_waveform)
         self.request_cancel_wave.connect(self._worker.cancel_ad9102_waveform_upload)
         self.request_save_profile.connect(self._worker.save_profile)
@@ -320,6 +322,16 @@ class MainWindow(QMainWindow):
             )
         )
 
+    def _on_apply_tec_modulation(self) -> None:
+        self._dispatch_command(
+            lambda: self.request_apply_tec_modulation.emit(
+                self._tec_mod_enable.isChecked(),
+                int(self._tec_mod_laser.currentData()),
+                self._tec_mod_frequency_hz.value(),
+                self._tec_mod_amplitude_code.value(),
+            )
+        )
+
     def _on_save_profile(self) -> None:
         dialog = ProfileSaveDialog(
             custom_waveform_available=self._custom_waveform_is_available(),
@@ -408,6 +420,7 @@ class MainWindow(QMainWindow):
         self._apply_ad9102_button.setEnabled(connected)
         self._apply_ad9833_button.setEnabled(connected)
         self._apply_stm32_dac_button.setEnabled(connected)
+        self._apply_tec_modulation_button.setEnabled(connected)
         self._pulse_ds1809_button.setEnabled(connected)
         self._upload_wave_button.setEnabled(connected)
         self._cancel_wave_button.setEnabled(connected)
@@ -724,6 +737,11 @@ class MainWindow(QMainWindow):
             f"stm32_dac_enable={1 if self._stm32_dac_enable.isChecked() else 0}",
             f"stm32_dac_code={self._stm32_dac_code.value()}",
             "",
+            f"tec_modulation_enable={1 if self._tec_mod_enable.isChecked() else 0}",
+            f"tec_modulation_laser={int(self._tec_mod_laser.currentData())}",
+            f"tec_modulation_frequency_hz={self._tec_mod_frequency_hz.value()}",
+            f"tec_modulation_amplitude_code={self._tec_mod_amplitude_code.value()}",
+            "",
             f"ds1809_apply={'true' if self._ds1809_profile_apply.isChecked() else 'false'}",
             f"ds1809_position_from_min={self._ds1809_profile_position.value()}",
         ]
diff --git a/laser_control/gui/worker.py b/laser_control/gui/worker.py
index 4197d9a..c6bcb0f 100644
--- a/laser_control/gui/worker.py
+++ b/laser_control/gui/worker.py
@@ -101,6 +101,22 @@ class ControllerWorker(QObject):
             )
         )
 
+    @pyqtSlot(bool, int, int, int)
+    def apply_tec_modulation(
+        self,
+        enabled: bool,
+        laser: int,
+        frequency_hz: int,
+        amplitude_code: int,
+    ) -> None:
+        """Configure fast TEC drive modulation."""
+        self._run_command(
+            lambda: (
+                self._ensure_connected(),
+                self._apply_tec_modulation_impl(enabled, laser, frequency_hz, amplitude_code),
+            )
+        )
+
     @pyqtSlot(object)
     def save_profile(self, request: object) -> None:
         """Save the current GUI configuration to the device SD card."""
@@ -256,6 +272,26 @@ class ControllerWorker(QObject):
         self.log_message.emit("INFO", f"STM32 DAC set to code {dac_code}")
         self._emit_status()
 
+    def _apply_tec_modulation_impl(
+        self,
+        enabled: bool,
+        laser: int,
+        frequency_hz: int,
+        amplitude_code: int,
+    ) -> None:
+        self._controller.configure_tec_modulation(
+            enabled=enabled,
+            laser=laser,
+            frequency_hz=frequency_hz,
+            amplitude_code=amplitude_code,
+        )
+        state = "enabled" if enabled else "disabled"
+        self.log_message.emit(
+            "INFO",
+            f"TEC modulation {state}: laser={laser}, frequency={frequency_hz} Hz, amplitude={amplitude_code}",
+        )
+        self._emit_status()
+
     def _save_profile_impl(self, request: object) -> None:
         self._controller.save_profile_to_sd(request)
         profile_name = getattr(request, "profile_name", "<unnamed>")
diff --git a/laser_control/protocol.py b/laser_control/protocol.py
index 949433a..5ee265f 100644
--- a/laser_control/protocol.py
+++ b/laser_control/protocol.py
@@ -29,6 +29,7 @@ from .constants import (
     CMD_DS1809_CONTROL,
     CMD_STATE,
     CMD_STM32_DAC_CONTROL,
+    CMD_TEC_MODULATION_CONTROL,
     CMD_TRANS_ENABLE,
     DEFAULT_SETUP_WORD,
     DS1809_FLAG_DECREMENT,
@@ -46,6 +47,8 @@ from .constants import (
     SEND_PARAMS_TOTAL_LENGTH,
     SHORT_CONTROL_TOTAL_LENGTH,
     STM32_DAC_FLAG_ENABLE,
+    TEC_MODULATION_FLAG_CHANNEL_2,
+    TEC_MODULATION_FLAG_ENABLE,
     STATUS_DESCRIPTIONS,
     STATUS_RESPONSE_LENGTH,
     WAVE_DATA_TOTAL_LENGTH,
@@ -270,6 +273,25 @@ class Protocol:
             0,
         )
 
+    @staticmethod
+    def encode_tec_modulation_control(
+        *,
+        enabled: bool,
+        laser: int,
+        frequency_hz: int,
+        amplitude_code: int,
+    ) -> bytes:
+        """Build a TEC drive-modulation control packet."""
+        flags = TEC_MODULATION_FLAG_ENABLE if enabled else 0
+        if laser == 2:
+            flags |= TEC_MODULATION_FLAG_CHANNEL_2
+        return Protocol._encode_short_control(
+            CMD_TEC_MODULATION_CONTROL,
+            flags,
+            _ensure_uint(frequency_hz, "frequency_hz", 0, 0xFFFF),
+            _ensure_uint(amplitude_code, "amplitude_code", 0, 0xFFFF),
+        )
+
     @staticmethod
     def encode_ad9102_wave_begin(sample_count: int) -> bytes:
         """Build an AD9102 custom-wave upload BEGIN packet."""