diff --git a/dcs/frames/ch06_mixer.py b/dcs/frames/ch06_mixer.py
new file mode 100644
index 0000000..cf4cf0b
--- /dev/null
+++ b/dcs/frames/ch06_mixer.py
@@ -0,0 +1,272 @@
+#  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
+
+from tkinter import ttk, LEFT, BOTH, BOTTOM
+from pydantic import confloat
+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 Ch06Group
+from dcs.utils import swap_freq, abs_log_fft
+from typing import List
+from enum import Enum
+
+import matplotlib
+matplotlib.use('TkAgg')
+from matplotlib.figure import Figure
+from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg, NavigationToolbar2Tk
+
+
+SAMPLE_LEN = 512
+FFT_OVERSAMPLING = 64
+
+
+@ui_create
+class Function(ConfigObject):
+    freq: confloat(ge=-16*SAMPLE_LEN, lt=16*SAMPLE_LEN, multiple_of=(4.0/FFT_OVERSAMPLING)) = 1.0
+    amplitude_dB: confloat(ge=-100.0, lt=10.0, multiple_of=1) = 0.0
+    phase: confloat(ge=-180.0, le=180.0, multiple_of=0.1) = 0.0
+    offset: confloat(ge=-5.0, lt=5.0, multiple_of=0.01) = 0.0
+
+    def make_config_widget(self, parent: ttk.Widget) -> ConfigControlFrame:
+        frm = ConfigControlFrame(parent)
+
+        ttk.Label(frm, text='Frequency:').grid(row=0, column=0)
+        w = self.ui_create_freq(frm)
+        frm.add_widget(w)
+        w.grid(row=0, column=1)
+
+        ttk.Label(frm, text='Amplitude:').grid(row=1, column=0)
+        w = self.ui_create_amplitude_dB(frm)
+        frm.add_widget(w)
+        w.grid(row=1, column=1)
+        ttk.Label(frm, text='dB').grid(row=1, column=2)
+
+        ttk.Label(frm, text='Phase:').grid(row=2, column=0)
+        w = self.ui_create_phase(frm)
+        frm.add_widget(w)
+        w.grid(row=2, column=1)
+        ttk.Label(frm, text='°').grid(row=2, column=2)
+
+        ttk.Label(frm, text='Offset:').grid(row=3, column=0)
+        w = self.ui_create_offset(frm)
+        frm.add_widget(w)
+        w.grid(row=3, column=1)
+
+        return frm
+
+    def calc_signal(self, t: np.ndarray) -> np.ndarray:
+        phasor = np.power(10, self.amplitude_dB / 20) * np.exp(1j * self.phase * np.pi / 180)
+        phi = np.exp(1j * 2 * np.pi * self.freq * t)
+        return self.offset + (phasor * phi)
+
+    def make_title(self):
+        return f'f={self.freq}, {self.amplitude_dB} dB, {self.phase}°'
+
+
+class Direction(str, Enum):
+    UP = 'Up Conversion'
+    DOWN = 'Down Conversion'
+
+
+@ui_create
+class ConfigCh06Mixer(ConfigObject):
+    _KEY = 'ch06_mixer'
+
+    input_funcs: List[Function] = [
+        Function(freq=-1.0, amplitude_dB=0.0, phase=0.0),
+        Function(freq=2.0, amplitude_dB=0.0, phase=90.0),
+    ]
+    direction: Direction = Direction.UP
+    nco: Function = Function(freq=20.0, amplitude_dB=0.0)
+
+    def make_config_widget(self, parent: ttk.Widget) -> ConfigControlFrame:
+        frm = ConfigControlFrame(parent, borderwidth=1, relief='raised')
+
+        ttk.Label(frm, text='Input Functions:').pack()
+        w = self.ui_create_input_funcs_list(frm, lambda e: e.make_title())
+        frm.add_widget(w)
+        w.pack()
+
+        frm1 = ttk.Frame(frm)
+        frm1.pack()
+        ttk.Label(frm1, text='Conversion Direction:').grid(row=0, column=0)
+        w = self.ui_create_direction_dropdown(frm1)
+        frm.add_widget(w)
+        w.grid(row=0, column=1)
+
+        frm2 = ttk.Frame(frm, borderwidth=1, relief='raised')
+        frm2.pack()
+        ttk.Label(frm2, text='Carrier:').pack()
+        carrier_frm = self.nco.make_config_widget(frm2)
+        for w in carrier_frm.ctrl_widgets:
+            frm.add_widget(w)
+        carrier_frm.pack()
+
+        return frm
+
+    def calc_oscillator_signal(self, t: np.ndarray) -> np.ndarray:
+        if self.direction == Direction.UP:
+            return self.nco.calc_signal(t)
+        elif self.direction == Direction.DOWN:
+            return np.conjugate(self.nco.calc_signal(t))
+        else:
+            raise Exception('Invalid direction')
+
+    def calc_input_signal(self, t: np.ndarray) -> np.ndarray:
+        x = np.zeros((len(self.input_funcs), len(t)), dtype='complex128')
+        for index, func in enumerate(self.input_funcs):
+            x[index, :] = func.calc_signal(t)
+        return np.sum(x, axis=0)
+
+    def calc_output_signal(self, t: np.ndarray) -> np.ndarray:
+        inp = self.calc_input_signal(t)
+        carrier = self.calc_oscillator_signal(t)
+        re_mixed = (np.real(inp) * np.real(carrier)) - (np.imag(inp) * np.imag(carrier))
+        im_mixed = (np.imag(inp) * np.real(carrier)) + (np.real(inp) * np.imag(carrier))
+        return re_mixed + (1j * im_mixed)
+
+
+class Ch06MixerFrame(BaseFrame):
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        self._config: ConfigCh06Mixer = default_store().get_config(ConfigCh06Mixer)
+
+        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.draw_td()
+        self.draw_fd()
+
+    def _create_signal_tabs(self) -> ttk.Widget:
+        tabs = ttk.Notebook(self)
+
+        td_frm = ttk.Frame(tabs)
+        tabs.add(td_frm, text='Time Domain')
+        self._td_fig = Figure(figsize=(12, 6), dpi=100)
+        self._td_canvas = FigureCanvasTkAgg(self._td_fig, td_frm)
+        self._td_canvas.get_tk_widget().pack(expand=True, fill=BOTH)
+        td_tb = NavigationToolbar2Tk(self._td_canvas, td_frm, pack_toolbar=False)
+        td_tb.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)
+
+        self.draw_td()
+        self.draw_fd()
+
+        return tabs
+
+    def draw_td(self):
+        self._td_fig.clear()
+
+        ax_inp = self._td_fig.add_subplot(3, 1, 1)
+        ax_inp.set_xlim(0.0, 1.0)
+        ax_inp.set_xlabel('time')
+        ax_inp.set_ylabel('value')
+        ax_inp.set_title('Input Signal')
+        ax_nco = self._td_fig.add_subplot(3, 1, 2)
+        ax_nco.set_xlim(0.0, 1.0)
+        ax_nco.set_xlabel('time')
+        ax_nco.set_ylabel('value')
+        ax_nco.set_title('Numerically-Controlled Oscillator Signal')
+        ax_out = self._td_fig.add_subplot(3, 1, 3)
+        ax_out.set_xlim(0.0, 1.0)
+        ax_out.set_xlabel('time')
+        ax_out.set_ylabel('value')
+        ax_out.set_title('Output Signal')
+
+        t = np.arange(0, SAMPLE_LEN, 1) / SAMPLE_LEN
+
+        x_inp = self._config.calc_input_signal(t)
+        ax_inp.plot(t, np.real(x_inp), label='Input Re (I)', linestyle='solid', color='blue', linewidth=1)
+        ax_inp.plot(t, np.imag(x_inp), label='Input Im (Q)', linestyle='solid', color='red', linewidth=1)
+        ax_inp.legend()
+
+        x_nco = self._config.calc_oscillator_signal(t)
+        ax_nco.plot(t, np.real(x_nco), label='NCO Re (I)', linestyle='solid', color='green', linewidth=1)
+        ax_nco.plot(t, np.imag(x_nco), label='NCO Im (Q)', linestyle='solid', color='orange', linewidth=1)
+        ax_nco.legend()
+
+        x_out = self._config.calc_output_signal(t)
+        ax_out.plot(t, np.real(x_out), label='Output Re (I)', linestyle='solid', color='blue', linewidth=1)
+        ax_out.plot(t, np.imag(x_out), label='Output Im (Q)', linestyle='solid', color='red', linewidth=1)
+        ax_out.legend()
+
+        self._td_fig.tight_layout()
+        self._td_canvas.draw()
+
+    @classmethod
+    def _log_real(cls, x: np.ndarray) -> np.ndarray:
+        return np.real(x)
+
+    @classmethod
+    def _log_imag(cls, x: np.ndarray) -> np.ndarray:
+        return np.imag(x)
+
+    @classmethod
+    def _log_abs(cls, x: np.ndarray) -> np.ndarray:
+        return np.abs(x)
+
+    def draw_fd(self):
+        self._fd_fig.clear()
+
+        ax_inp = self._fd_fig.add_subplot(2, 1, 1)
+        ax_inp.set_xlim(-int(SAMPLE_LEN/2), int(SAMPLE_LEN/2))
+        ax_inp.set_xlabel('frequency')
+        ax_inp.set_ylabel('value (dB)')
+        ax_inp.set_title('Input Signals')
+        ax_out = self._fd_fig.add_subplot(2, 1, 2)
+        ax_out.set_xlim(-int(SAMPLE_LEN/2), int(SAMPLE_LEN/2))
+        ax_out.set_xlabel('frequency')
+        ax_out.set_ylabel('value (dB)')
+        ax_out.set_title('Output Signal')
+
+        t_ovs = np.arange(0, (SAMPLE_LEN * FFT_OVERSAMPLING), 1) / SAMPLE_LEN
+        f_ovs = swap_freq(np.fft.fftfreq(t_ovs.shape[-1], 1.0/SAMPLE_LEN))
+
+        x_inp = self._config.calc_input_signal(t_ovs)
+        x_nco = self._config.calc_oscillator_signal(t_ovs)
+        ax_inp.plot(f_ovs, abs_log_fft(x_inp), label='Input', linestyle='solid', color='blue', linewidth=1)
+        ax_inp.plot(f_ovs, abs_log_fft(x_nco), label='NCO', linestyle='solid', color='green', linewidth=1)
+        ax_inp.legend()
+
+        x_out = self._config.calc_output_signal(t_ovs)
+        ax_out.plot(f_ovs, abs_log_fft(x_out), label='Output', linestyle='solid', color='brown', linewidth=1)
+        ax_out.legend()
+
+        self._fd_fig.tight_layout()
+        self._fd_canvas.draw()
+
+
+class Ch06MixerWindow(Window):
+    GROUP = Ch06Group
+    TITLE = 'Digital Mixer'
+    FRAME = Ch06MixerFrame
+
+
+if __name__ == '__main__':
+    Ch06MixerWindow.main()
+