Finally, an affordable signal generator for everyone!

ERASynth is a high quality portable signal generator at a price point affordable by everyone including makers, students, universities, research labs, and start-ups.

Makers/Hackers

RF signal generators are expensive pieces of test equipment typically only accessible by pro engineers. ERASynth removes the cost barriers and makes quality RF signal synthesis accessible to everyone, especially budget-conscious makers.

Students

ERASynth is for everyone who wants to learn how signal generators work. Since it is open source with open schematics, students or anyone who is curious about the inner details of signal synthesis can learn from ERASynth. You can learn a lot by reverse engineering and hacking, without having to pay $50k in tuition in engineering program. After all, learning the design of test equipment turned Jim Williams into one of the best analog engineers in the world. ERASynth’s advanced design will certainly teach you several RF tricks.

Professionals

Professional engineers will find ERASynth is a very good alternative to many of their existing signal generators. If you are professional engineer, you can compare it yourself: find the lowest cost equipment on your bench that can give you a 1 GHz signal with -120 dBc/Hz or better phase noise at 10 kHz offset. Its price tag will be several times more than ERASynth’s. See the comparison charts below to learn more about how ERASynth compares to common signal generators.

Professors/Researchers/Start-ups

With all the cuts in research funds, who can afford to spend tens of thousands on signal generators? Whether you are a college professor studying Gigasample converters or a start-up developing state-of-the-art converter technology, you need to clock ADC/DAC somehow. Check out the specs, you will find ERASynth may very well be your next clock source. Besides the price, ERASynth’s portability will definitely help when you are out in the field.

Anyone Else

ERASynth is for anyone interested in RF testing. Below is a short list of application areas where users can take advantage of ERASynth:

• General purpose RF testing. For example, to measure the gain of an amplifier, ERASynth can be used as the source.
• Test signal source for SDR. People who are using any of the many SDR platforms can use ERASynth as the test signal source for testing and calibration of their SDR devices.
• An agile LO source for up and down-converters.
• Clock source for ADCs and DACs. When equipped with an optional OCXO, ERASynth's jitter performance exceeds the requirements of state-of-the-art giga-sample data-converters.

Features & Specifications

• Architecture: Multiloop Integer-N PLL driven by a tunable reference. No fractional-N or integer boundary spurs
• Frequency Range:
  • ERASynth: 250 kHz to 6 GHz
  • ERASynth+: 250 kHz to 15 GHz
  • ERASynth++: 250 kHz to 20 GHz
• Amplitude Range: -60 to +15 dBm
• Phase Noise: -120 dBc/Hz, typical phase noise @ 1 GHz output and 10 kHz offset
• Frequency Switching Time: 250 µs
• Reference: Ultra-low noise 100 MHz VCXO locked to a
  • ±0.5 ppm TCXO for ERASynth
  • ±25 ppb OCXO for ERASynth+ and ERASynth++
• MCU: Arduino Due board with BGA package Atmel Microcontroller (ATSAM3X8EA-CU)
• Interfaces:
  • Wi-Fi interface for web-based GUI access
  • Mini USB for serial access
  • Micro USB for power input
  • Microphone jack for audio input
  • Trigger Input (SMA) for triggered sweep / External modulation input
  • REF In (SMA) for external reference input
  • REF Out (SMA) for 10 MHz reference output
  • RF Out
• Dimensions: 10.5 cm x 14.5 cm x 2 cm
• Weight: < 400 g (14.1 oz)
• Power Input: 5 to 12 V
• Power Consumption:
  • < 6 W for ERASynth
  • < 7 W for ERASynth+ and ERASynth++
• Enclosure: Precision-milled, nickel-plated aluminum case
• Open Source: Schematics, embedded Arduino code, Web GUI source code, and RS-232 command set

Signal Generator Architecture: Multiloop with a Tunable Reference vs Single Loop Fractional-N

Low cost, USB-controlled RF signal generators are available from a multitude of vendors. These signal generators usually include a single fractional PLL IC with integrated VCO. Examples of such PLL ICs are: ADF435x and ADF5355 series from ADI, LMX series from TI, MAX2870 from Maxim, and STuW series from STMicro. These signal generators are mostly a close replica of the eval board of the PLL/VCO IC and they are usually limited in terms of performance. ERASynth architecture provides several built-in features that overcome these limitations.

ERASynth rev3.1 block diagram

Competitor block diagram

ERASynth Eliminates Integer Boundary Spurs

While fractional-N PLLs are great for generating frequencies with fine frequency resolution, they suffer from a phenomenon called "integer boundary spurs" (IB spurs). IB spurs are visible at the output of a frac-N PLL IC when the output frequency is close to an integer multiple of the reference frequency. For example, generating an RF output of 6000.01 GHz from a 100 MHz reference will result in IB spurs as large as -30 dBc. This level of performance may be acceptable for some specific application, but generally it is unacceptable for signal generators. ERASynth’s multi-loop architecture eliminates IB spurs by varying the reference in fine steps while keeping the main loop in integer-N mode. This architecture not only diminishes IB spurs but also helps reduce phase noise. PLL IC’s phase noise floors are usually lower by 2-3 dB in integer-N mode compared to frac-N mode.

ERASynth rev2 (turquoise) vs ADF5355 Eval Board (yellow) @ 6.14401418 GHz. ERASynth rev2 uses ADF4356 as the main PLL.

ERASynth Improves Phase Noise

On top of the dual loop PLL that generates the RF output, ERASynth adds another PLL to minimize the reference phase noise. While many competitors use low-cost TCXOs in the range of a few tens of MHz, ERASynth uses a 100 MHz VCXO with a very low phase noise floor. This VCXO is stabilized with a ±0.5 ppm TCXO or ±25ppb OCXO depending on the model. The VCXO may also be locked to an external 10 MHz reference.

ERASynth rev3.1 phase noise at 10 GHz RF output.

ERASynth rev3.1 phase noise at 1 GHz RF output.

ERASynth rev3.1 phase noise at 100 MHz RF output.

ERASynth rev3.1 phase noise at 10 MHz RF output.

ERASynth rev3.1 10 MHz REF OUT phase noise.

Comparisons: ERASynth vs. Low-cost USB Signal Generators

Comparisons: ERASynth vs. Professional Bench-Top RF Signal Generators

Support & Documentation

ERASynth schematics, Arduino firmware, web and Windows GUI source codes, datasheet and user guide are all available on ERA Instruments GitHub repository.

• ERASynth Datasheet
• ERASynth User's Guide