MixNV Active Mixer – RF Upconverter And Downconverter


1 MHz – 6 GHz USB Powered and Programmed RF Mixer and RF Signal Generator

The Windfreak MixNV is a 1MHz to 6GHz software programmable RF mixer which can up-convert, down-convert, or act as an RF Signal Generator. It has a built-in Phase Locked Local Oscillator controlled and powered by a PC running Windows, Android, or Linux via its USB port. Android and Linux require free 3rd party command line terminal software.

The oscillator will tune from 85MHz to 4.2GHz in 1Hz steps using an advanced sigma-delta modulator PLL that delivers low fractional spurious products and excellent phase noise. The oscillator tunes to 5GHz with reduced performance.

The MixNV also has nonvolatile onboard memory so it can be programmed to fire up by itself to any LO frequency, FSK modulation, or other settings. This allows the end-user to put it in a box or rack without the need for PC control.

In Stock. Ships within 5 business days.

The MixNV is designed as a stand-alone mixer for use in RF and Microwave communications products or test setups but has the ability to self bias the mixer such that it can be used as a signal generator with fine frequency resolution. It also has the ability to perform 2 level FSK (Frequency Shift Keyed) Modulation with finely adjustable frequency deviation via software or offboard external 3.3V cmos drive. Use the open-source Windfreak software, or the device can be controlled easily with 3rd party programs such as Hyperterminal or other freeware serial communications terminals across many operating systems.

Case Dimensions including mounting tabs: 2.5″ X 1.375″ X 0.75″ (6.35cm X 3.5cm X 1.9cm)

Block Diagram: (Note: The external FSK connection is available inside on the PCB but not through the case.)

Active RF Mixer with build in PLL LO

Shown below, the software is eloquently engineered giving a professional performance at a fraction of the cost of a separate mixer plus RF synthesizer solution.

Main tab for frequency and mode setting. (Both modes shown – Mixer and LO Mode)


FM Modulation Tab. Enter deviation and rate. Also manually toggle between FSK frequencies with Mod Bit for fine tuning.


Shown is 10.123KHz deviation FSK.


Extras Tab. Save all settings to MixNV EEPROM and read the firmware version. Also choose external or 10MHz internal reference.


USB Communications Tab. Scan for devices connected and determine the built-in serial number.


This software was written in Labview. The open source code is included so that you can modify and enhance any way you see fit for your own use. Please do not distribute. If you don’t own Labview, you will also get the executable that will install stand-alone and run on a PC. (Note: The Labview development system is available with a free 1 month trial from National Instruments.) All source code is sent on CD “saved as” using the latest version of Labview Basic.

The MixNV is also very easy to control without using the Windfreak supplied software. Click the link below to see the format for MixNV serial communications and how to use 3rd party (free) software to control the device on windows or any other operating system. With this format of serial communications, writing your own control software will be very easy.

**The MixNV has been tested with a terminal program from the Google Play market called “Android USB Serial”. This app is currently free. The only hardware it has been tested with to date is the Samsung Galaxy Note 1. To act as a USB host the phone needs a USB dongle which is about a $15 cable from Amazon. The Galaxy Note is successfully able to power the MixNV making it one of the most portable RF Signal Generators in the world. If you have success with your phone, please drop us an email so we can add it to the list of compatible hardware.

Local Oscillator accuracy is based on an onboard 2.5ppm 10MHz crystal oscillator, which is also routed to the outside world via the reference SMA connector. This connector can also be used to input a higher precision reference if so desired. The external reference can range from 10MHz to 100MHz. Internal or External reference selection is made via software.

The operating temperature range of the MixNV is -40C to +85C.

The MixNV will run off USB power via its USB mini connector.  It will also run standalone via its 5 (+/-0.5) volt DC power connector. Current draw is 150mA. The center pin is positive and the outer conductor is ground.

Compare this unit to other less integrated solutions worth thousands of dollars. Windfreak Technologies has invested hundreds of man hours on software that you get to build upon for highly custom applications.  The Labview source code is included with your purchase.

Some applications include: wireless communications systems, SDR, microwave point to point backhaul radios, Automated Test Equipment (ATE), frequency upconversion, frequency downconversion, Local Oscillator (LO) replacement, transverters, and hobbyist radio development.

For orders over 10 units volume discounts will apply. Request a quote via this Web Form . Emails will be answered within 24 hours. Keep an eye on your SPAM folder. You will be given a lead time (usually ships right away) and a quote if you desire large volume.

Weight 1.5 lbs
Dimensions 7 × 5 × 2 in

Feature List

  • Open source Labveiw GUI software control via USB
  • Run hardware functions with or without a PC
  • Use as an RF Mixer or as an RF Signal Generator
  • Upconvert or Downconvert
  • 1Hz frequency resolution PLL
  • Mixer input frequencies from 1MHz – 6GHz
  • Mixer output frequencies from 5MHz – 4.5GHz
  • LO output frequencies from 85MHz – 5GHz
  • 3mS LO RF lock time standard
  • Up to +7dBm signal generator output power
  • 10MHz – 100MHz external reference input
  • 5ppm internal 10MHz reference
  • Internal and external Frequency Shift Modulation
  • 5″ X 1.375″ X 0.75″ (6.35cm X 3.5cm X 1.9cm)


Active RF Mixer with build in PLL LO
MixNV RF Mixer Block Diagram

1. Electrical Characteristics

Supply Voltage456VFrom Power Plug
Supply Voltage *14.556VFrom USB Connector
Supply Current120200mA
Mixer Input Frequency Range1-6000MHz
Mixer Output Frequency Range54500MHz
LO Frequency Range854200MHzOver full temperature range
LO Frequency Range855000MHzAt room temperature
LO RF Output Power7dBmSee Section 2.1 Graphs
Down Conversion Gain-7dBOutput at 5MHz – 500MHz
Up Conversion Gain-10-7dBSee Section 2.3 Graphs
RF Input / Output Impedance50
RF Input Maximum Power12dBm
RF Input P1dB10dBmMixer Mode Linearity = 7
Phase Noise (LO = 1GHz)-108dBc/Hz100MHz Ext Reference
10KHz Offset-9810MHz Int Reference
Phase Noise (LO = 2GHz)-102dBc/Hz100MHz Ext Reference
10KHz Offset-9210MHz Int Reference
Phase Noise (LO = 3GHz)-98dBc/Hz100MHz Ext Reference
10KHz Offset-8810MHz Int Reference
Phase Noise (LO = 4GHz)-96dBc/Hz100MHz Ext Reference
10KHz Offset-8610MHz Int Reference
Mixer Noise Figure15dBMixer Mode Linearity = 7
11Mixer Mode Linearity = 2
IIP323dBmMixer Mode Linearity = 5
(See Section 2.6)10Mixer Mode Linearity = 1
Internal Reference Frequency10MHz
Internal Reference Tolerance2.5ppm
External Reference Frequency10-100MHz
External Reference Level In12VppCMOS or Clipped Sine
Internal Reference Level Out17dBmSquare CMOS 10MHz

2. Typical Performance

2.1 LO Mode RF Output Power

The typical LO Mode output power of the MixNV is shown below. The MixNV has two modes, Mixer Mode and LO Mode.  LO Mode biases the mixer and allows maximum LO feedthrough so the device can be used as a basic RF Signal Generator. The MixNV has a 3-bit power setting in LO Mode, settable from 0 (minimum power) to 7 (maximum power).

RF Signal Generator Output Power over frequency
RF Output Power for the MixNV


The minimum power setting of 0 is LO feed through and very low power as shown in the next graph.

RF Signal Generator Lowest Power Setting
RF Signal Generator Lowest Power Setting

2.2 LO Mode RF Output Harmonic Content

The typical MixNV LO Mode harmonic distortion is shown below for the second and third harmonics.  This data is taken at the maximum LO power setting of 7 and shown in dBc.

If lower harmonic levels are needed, Windfreak Technologies suggest the use of low cost SMA filters from Crystek.  A $25 1GHz example would be the CLPFL-1000.  There are usually many different frequency cut-offs in stock at Digikey.

MixNV Harmonic Distortion
RF Mixer Harmonic Distortion

2.3 Mixer Mode Conversion Gain

The MixNV has a dedicated input and output.  It is not bi-directional.  The Gilbert Cell mixer itself is passive and thus has negative gain.  To use this device as an upconverter or downconverter it should be treated as a normal mixer with consideration to LO feedthrough, Upper Side Band and Lower Side Band images with associated spectral inversions, input RF feedthrough and all associated harmonics and their products.

All plots in this section are made with a Mixer Linearity Setting of 3.

1GHz RF Input Downconversion Gain
RF Mixer Downconverter with 1GHz Input
1GHz RF Input Downconversion Gain
RF Mixer Downconverter with 1GHz Input
RF Mixer Downconversion gain across frequency.
Upconversion Gain of the MixNV RF Mixer
MixNV Upconversion gain
RF Mixer Downconversion gain across frequency.

2.4 LO Feedthrough

LO feedthrough in Mixer Mode with 50 ohm terminated input and no input signal.

MixNV RF Mixer Local Oscillator Feedthrough
RF Mixer Local Oscillator Feedthrough across frequency

2.5 LO Phase Noise

Phase noise in LO Mode and Mixer Mode will be similar.  Phase noise on the local oscillator is better at low RF carrier frequencies and gets worse at higher frequencies.  See plot for typical phase noise at 2.6GHz with two different reference options.  Phase noise (and frequency accuracy in general) can be made better with an external reference.  Higher reference frequencies yield higher phase comparison frequencies and thus better phase noise.  The MixNV highest phase comparison frequency is 50 MHz, so it automatically divides the reference frequency by 2 when the reference frequency is over 50MHz.

MixNV Phase Noise Analysis
RF Mixer Local Oscillator Phase noise

2.6 Mixer Mode Intermodulation Distortion

In the Down Conversion example below the MixNV is fed two tones on either side of 1GHz at -10dBm with a 1MHz separation in each tone.  The LO is set to 900 MHz low side injection giving a 100MHz IF output with 7dB of loss in the fundamental signal giving -17dBm of fundamental power in each output tone.  IMD is measured at roughly -83dBm.  This gives an OIP3 of +16dBm.  Factoring in the gain of the mixer stage gives +23dBm of IIP3.

MixNV Intermodulation Distortion IMD Analysis
RF Mixer Intermodulation Distortion performance

3. Mechanical Dimensions

MixNV RF Mixer Mechanical Dimensions
MixNV RF Mixer Mechanical Dimensions

Figure 1. Outer Dimensions in Inches


  • Wireless communications systems
  • RF and Microwave radios
  • Software Defined Radio (SDR)
  • $20 RTL-SDR 6GHz Frequency Extender
  • Superheterodyne Receiver
  • Frequency Up Conversion
  • Frequency Down Conversion
  • Frequency Shift Key Modulator
  • Automated Test Equipment (ATE)
  • Radar
  • Quantum device research



  1. Datasheet
  2. Quickstart Guide
  3. Control Software GUI Download (hit Cancel during hardware search if demo-ing software)
  4. Serial Communication