diff --git a/dcs/frames/__init__.py b/dcs/frames/__init__.py
index a1a8023..1fd412d 100644
--- a/dcs/frames/__init__.py
+++ b/dcs/frames/__init__.py
@@ -22,6 +22,7 @@
 from .ch06_mixer import Ch06MixerWindow
 from .ch06_down_sampling import Ch06DownSamplingWindow
 from .ch06_up_sampling import Ch06UpSamplingWindow
+from .ch07_spreading import Ch07SpreadingWindow
 
 
 def get_windows() -> List[Type[base.Window]]:
@@ -41,6 +42,7 @@
         Ch06MixerWindow,
         Ch06DownSamplingWindow,
         Ch06UpSamplingWindow,
+        Ch07SpreadingWindow,
     ]
 
 
diff --git a/dcs/frames/ch07_spreading.py b/dcs/frames/ch07_spreading.py
new file mode 100644
index 0000000..f6abc8c
--- /dev/null
+++ b/dcs/frames/ch07_spreading.py
@@ -0,0 +1,319 @@
+#  SPDX-License-Identifier: MPL-2.0
+#    Copyright (c) 2022 Philipp Le <philipp@philipple.de>.
+#  This Source Code Form is subject to the terms of the Mozilla Public
+#  License, v. 2.0. If a copy of the MPL was not distributed with this
+#  file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+from __future__ import annotations
+
+import copy
+from tkinter import ttk, LEFT, BOTH, BOTTOM
+from pydantic import confloat, conint
+from dcs.config import default_store, ConfigObject, ui_create, ConfigControlFrame
+import numpy as np
+import scipy.signal
+from dcs.frames.base import BaseFrame, Window
+from dcs.frames.groups import Ch07Group
+from dcs.utils.chain import TxBasebandGenerator, RxCorrelationGenerator, RfBandGenerator
+from dcs.utils.filter import create_lp_filter_class, NoFilter
+from dcs.utils.iq_mixer import create_iq_oscillator_class, IqUpMixer, IqDownMixer, IqRfBandGenerator, \
+    IqRxBasebandGenerator, IqTxBasebandGenerator, IqOscillatorBase
+from dcs.utils.qam_modulation import ModulationMethod, QamBasebandModulator, QamBasebandGenerator
+from dcs.utils.symbols import MessageBinarySerializer, Symbols
+from dcs.utils.spreading import create_spreading_config_class, Spreader, Despreader, SpreadedBasebandSpectrum3D
+from typing import Dict, List
+
+import matplotlib
+matplotlib.use('TkAgg')
+from matplotlib.pyplot import Circle, Text
+from matplotlib.figure import Figure
+from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2Tk
+
+
+SAMPLE_RATE = 10000
+FFT_SAMPLES_PER_SYM = 128
+
+TxBasebandFilter = create_lp_filter_class(SAMPLE_RATE, 'TX Baseband')
+
+Spreading = create_spreading_config_class(SAMPLE_RATE)
+
+
+@ui_create
+class User(ConfigObject):
+    message: str = 'DCS'
+    spreading: Spreading = Spreading()
+    modulation: ModulationMethod = ModulationMethod.BPSK
+    tx_lp: TxBasebandFilter = TxBasebandFilter()
+
+    def make_config_widget(self, parent: ttk.Widget) -> ConfigControlFrame:
+        frm = ConfigControlFrame(parent)
+
+        frm1 = ConfigControlFrame(frm, borderwidth=1, relief='raised')
+        frm1.pack()
+        spreading_frame = self.spreading.make_config_widget(frm1)
+        spreading_frame.pack()
+
+        frm2 = ConfigControlFrame(frm, borderwidth=1, relief='raised')
+        frm2.pack()
+        ttk.Label(frm2, text='Message:').grid(row=0, column=0)
+        self.ui_create_message(frm2).grid(row=0, column=1)
+
+        ttk.Label(frm2, text='Modulation:').grid(row=1, column=0)
+        self.ui_create_modulation_dropdown(frm2).grid(row=1, column=1)
+
+        ttk.Label(frm2, text='TX Baseband Low Pass Cut-Off:').grid(row=2, column=0)
+        self.tx_lp.ui_create_cutoff(frm2).grid(row=2, column=1)
+        ttk.Label(frm2, text='Hz').grid(row=2, column=2)
+
+        return frm
+
+    def make_title(self):
+        return f'{self.message} - {self.spreading.make_title()}'
+
+    def get_symbols(self) -> Symbols:
+        return MessageBinarySerializer(self.message).to_symbols()
+
+    def make_unspreaded_signal(self) -> TxBasebandGenerator:
+        return QamBasebandGenerator(
+            self.get_symbols(),
+            QamBasebandModulator(
+                symbol_rate=self.make_spreader().get_symbol_rate(),
+                method=ModulationMethod.BPSK,
+                baseband_filter=NoFilter(),
+            )
+        )
+
+    def make_spreader(self) -> Spreader:
+        return self.spreading.make_spreader(self.modulation, self.tx_lp)
+
+    def make_despreader(self) -> Despreader:
+        return self.spreading.make_despreader(self.modulation, self.tx_lp)
+
+
+@ui_create
+class ConfigCh07Spreading(ConfigObject):
+    _KEY = 'ch07_spreading'
+
+    users: List[User] = [
+        User()
+    ]
+    #tx_osc: IqOscillator = IqOscillator(freq=100.0)
+    noise_dBc: confloat(ge=-160.0, le=40.0, multiple_of=0.1) = -60.0
+    random_seed: conint(ge=0, lt=10000) = 1000
+    #rx_osc: IqOscillator = IqOscillator(freq=100.0)
+    #rx_lp: RxBasebandFilter = RxBasebandFilter()
+
+    def _noise_frame(self, parent: ttk.Widget) -> ConfigControlFrame:
+        frm = ConfigControlFrame(parent, borderwidth=1, relief='raised')
+
+        ttk.Label(frm, text='Signal-Noise Ratio:').grid(row=0, column=0)
+        w = self.ui_create_noise_dBc(frm)
+        frm.add_widget(w)
+        w.grid(row=0, column=1)
+        ttk.Label(frm, text='dBc').grid(row=0, column=2)
+
+        ttk.Label(frm, text='Random Seed:').grid(row=1, column=0)
+        w = self.ui_create_random_seed(frm)
+        frm.add_widget(w)
+        w.grid(row=1, column=1)
+
+        return frm
+
+    def make_config_widget(self, parent: ttk.Widget) -> ConfigControlFrame:
+        frm = ConfigControlFrame(parent, borderwidth=1, relief='raised')
+
+        user_frm = ttk.Frame(frm, borderwidth=1, relief='raised')
+        user_frm.pack()
+        ttk.Label(user_frm, text='TX Oscillator:').pack()
+        w = self.ui_create_users_list(user_frm, lambda e: e.make_title())
+        frm.add_widget(w)
+        w.pack()
+
+        noise_frm = self._noise_frame(frm)
+        noise_frm.pack()
+        for w in noise_frm.ctrl_widgets:
+            frm.add_widget(w)
+
+        return frm
+
+
+class Ch07SpreadingFrame(BaseFrame):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self._config: ConfigCh07Spreading = default_store().get_config(ConfigCh07Spreading)
+
+        ctrl_frm = self._create_control()
+        ctrl_frm.pack(side=LEFT)
+
+        signal_frm = self._create_signal_tabs()
+        signal_frm.pack(expand=True, fill=BOTH)
+
+    def _create_control(self) -> ConfigControlFrame:
+        frm = self._config.make_config_widget(self)
+        frm.widgets_on_change(self._on_change)
+        return frm
+
+    def _on_change(self, _, __, ___):
+        default_store().save()
+        self.refresh()
+
+    def _create_signal_tabs(self) -> ttk.Widget:
+        tabs = ttk.Notebook(self)
+
+        tx_frm = ttk.Frame(tabs)
+        tabs.add(tx_frm, text='TX Baseband')
+        self._tx_fig = Figure(figsize=(12, 6), dpi=100)
+        self._tx_canvas = FigureCanvasTkAgg(self._tx_fig, tx_frm)
+        self._tx_canvas.get_tk_widget().pack(expand=True, fill=BOTH)
+        tx_tb = NavigationToolbar2Tk(self._tx_canvas, tx_frm, pack_toolbar=False)
+        tx_tb.pack(side=BOTTOM)
+
+        self._data_bytes = ttk.Label(tx_frm, text='')
+        self._data_bytes.pack(side=BOTTOM)
+        self._data_syms = ttk.Label(tx_frm, text='')
+        self._data_syms.pack(side=BOTTOM)
+
+        fd_frm = ttk.Frame(tabs)
+        tabs.add(fd_frm, text='Frequency Domain')
+        self._fd_fig = Figure(figsize=(12, 6), dpi=100)
+        self._fd_canvas = FigureCanvasTkAgg(self._fd_fig, fd_frm)
+        self._fd_canvas.get_tk_widget().pack(expand=True, fill=BOTH)
+        fd_tb = NavigationToolbar2Tk(self._fd_canvas, fd_frm, pack_toolbar=False)
+        fd_tb.pack(side=BOTTOM)
+
+        rx_frm = ttk.Frame(tabs)
+        tabs.add(rx_frm, text='RX Cross-Correlation')
+        self._rx_fig = Figure(figsize=(12, 6), dpi=100)
+        self._rx_canvas = FigureCanvasTkAgg(self._rx_fig, rx_frm)
+        self._rx_canvas.get_tk_widget().pack(expand=True, fill=BOTH)
+        rx_tb = NavigationToolbar2Tk(self._rx_canvas, rx_frm, pack_toolbar=False)
+        rx_tb.pack(side=BOTTOM)
+
+        self.refresh()
+
+        return tabs
+
+    def refresh(self):
+        if len(self._config.users) > 0:
+            user0 = self._config.users[0]
+            user0_spreader = user0.make_spreader()
+            tx_gen0 = user0_spreader.make_tx_baseband_generator(user0.get_symbols())
+
+            unspreaded_gen0 = user0.make_unspreaded_signal()
+
+            tx_gens = copy.deepcopy(tx_gen0)
+            for user in self._config.users[1:]:
+                tx_gens += user.make_spreader().make_tx_baseband_generator(user.get_symbols())
+
+            class _Osc(IqOscillatorBase):
+                def make_config_widget(self, parent: ttk.Widget) -> ConfigControlFrame:
+                    pass  # Won't be called
+
+            rf_gen = IqRfBandGenerator(
+                tx_gens,
+                IqUpMixer(
+                    tx_osc=_Osc(freq=0),
+                    noise_dBc=self._config.noise_dBc,
+                    random_seed=self._config.random_seed,
+                )
+            )
+            # rx_gen = rf_gen.make_iq_down_mixer(
+            #     IqDownMixer(
+            #         rx_osc=_Osc(freq=0),
+            #         baseband_filter=NoFilter(),
+            #     )
+            # )
+
+            rx_gen = user0.make_despreader().make_rx_correlation_generator(rf_gen)
+
+            # Draw
+            self.draw_tx(tx_gen0, unspreaded_gen0, rf_gen)
+            self.draw_fd(rf_gen, user0_spreader)
+            self.draw_rx(rx_gen, unspreaded_gen0)
+
+    def draw_tx(self, tx_gen0: TxBasebandGenerator, unspreaded_gen0: TxBasebandGenerator, rf_gen: RfBandGenerator):
+        self._tx_fig.clear()
+
+        ax_msg = self._tx_fig.add_subplot(3, 1, 1)
+        ax_msg.set_xlabel('time')
+        ax_msg.set_ylabel('value')
+        ax_msg.set_title('User 0 Message (Binary)')
+        ax_u0 = self._tx_fig.add_subplot(3, 1, 2)
+        ax_u0.set_xlabel('time')
+        ax_u0.set_ylabel('value')
+        ax_u0.set_title('User 0 TX Baseband Signal')
+        ax_tx = self._tx_fig.add_subplot(3, 1, 3)
+        ax_tx.set_xlabel('time')
+        ax_tx.set_ylabel('value')
+        ax_tx.set_title('TX Baseband Signal')
+
+        sig_msg = unspreaded_gen0.generate_tx_baseband_signal(SAMPLE_RATE)
+        ax_msg.set_xlim(np.min(sig_msg.t), np.max(sig_msg.t))
+        ax_msg.plot(sig_msg.t, np.real(sig_msg.signal), label='Message', color='blue', linewidth=1)
+
+        sig_u0 = tx_gen0.generate_tx_baseband_signal(SAMPLE_RATE)
+        ax_u0.set_xlim(np.min(sig_u0.t), np.max(sig_u0.t))
+        ax_u0.plot(sig_u0.t, np.real(sig_u0.signal), label='User 0', color='red', linewidth=1)
+
+        sig_tx = rf_gen.generate_rf_signal(SAMPLE_RATE)
+        ax_tx.set_xlim(np.min(sig_tx.t), np.max(sig_tx.t))
+        ax_tx.plot(sig_tx.t, np.real(sig_tx.signal), label='Baseband', color='brown', linewidth=1)
+
+        self._tx_fig.tight_layout()
+        self._tx_canvas.draw()
+
+    def draw_fd(self, rf_gen: RfBandGenerator, spreader: Spreader):
+        self._fd_fig.clear()
+
+        ax_fd = self._fd_fig.add_subplot(1, 1, 1, projection='3d')
+        ax_fd.set_xlabel('frequency')
+        ax_fd.set_ylabel('symbol')
+        ax_fd.set_zlabel('value (logarithmic)')
+        ax_fd.set_title('HF Signal Frequency-Domain')
+        ax_fd.set_zlim(-120, 40)
+
+        x, y, z = SpreadedBasebandSpectrum3D(
+            rf_gen,
+            spreader.get_symbol_rate(),
+            FFT_SAMPLES_PER_SYM
+        ).make_plot_data()
+
+        ax_fd.plot_trisurf(x, y, z)
+
+        self._fd_fig.tight_layout()
+        self._fd_canvas.draw()
+
+    def draw_rx(self, rx_correlation: RxCorrelationGenerator, unspreaded_gen0: TxBasebandGenerator):
+        self._rx_fig.clear()
+
+        ax_msg = self._rx_fig.add_subplot(2, 1, 1)
+        ax_msg.set_xlabel('time')
+        ax_msg.set_ylabel('value')
+        ax_msg.set_title('User 0 Message (Binary)')
+        ax_correlation = self._rx_fig.add_subplot(2, 1, 2)
+        ax_correlation.set_xlabel('time')
+        ax_correlation.set_ylabel('value')
+        ax_correlation.set_title('RX Correlation')
+
+        sig_msg = unspreaded_gen0.generate_tx_baseband_signal(SAMPLE_RATE)
+        ax_msg.set_xlim(np.min(sig_msg.t), np.max(sig_msg.t))
+        ax_msg.plot(sig_msg.t, np.real(sig_msg.signal), label='Message', color='blue', linewidth=1)
+
+        corr = rx_correlation.generate_rx_correlation(SAMPLE_RATE)
+        ax_correlation.set_xlim(np.min(corr.t), np.max(corr.t))
+        ax_correlation.plot(corr.t, np.real(corr.signal), label='Correlation', color='blue', linewidth=1)
+
+        self._rx_fig.tight_layout()
+        self._rx_canvas.draw()
+
+
+class Ch07SpreadingWindow(Window):
+    GROUP = Ch07Group
+    TITLE = 'Spread Spectrum'
+    FRAME = Ch07SpreadingFrame
+
+
+if __name__ == '__main__':
+    Ch07SpreadingWindow.main()
+
diff --git a/dcs/frames/groups.py b/dcs/frames/groups.py
index 4a5a0f2..7db939d 100644
--- a/dcs/frames/groups.py
+++ b/dcs/frames/groups.py
@@ -25,3 +25,7 @@
 
 class Ch06Group(Group):
     NAME = 'Chapter 06'
+
+
+class Ch07Group(Group):
+    NAME = 'Chapter 07'