Here are some answers to common questions we have been receiving about the ERASynth.

Q: How do you keep the output clean with an on-board Wi-Fi module? Doesn’t the WLAN signal radiated by the Wi-Fi module leak to RF output?

A: This questions is covered in our second campaign update.

Q: Do you plan to provide an app to control the ERASynth, or is it going to be purely web-based?

A: The control GUI is purely web-based, hence we will not provide any app for ERASynth. There are several reasons for that. Firstly, web GUI is platform independent. Secondly, it is more reasonable to support one web app instead of so many apps on different platforms. Lastly, the web GUI is very responsive and mimics apps very closely. It is almost like an app, looks and feels like an app. A demo and several screen shots of the web GUI may be found in our first campaign update.

Q: What is phase noise and why is it important?

A: Phase noise is a metric that quantifies the phase fluctuations of a sine wave in frequency domain. Ideally, a sine wave in time domain is a single line in the frequency domain. However, non-idealities in the components spread the line around and make it look more like a skirt. When looking from signal synthesis perspective, phase noise is the most important parameter. Achieving low phase noise is a challenging undertaking, especially with a low budget. To have a low phase noise signal in the multi-GHz range, you first need to start with a low phase noise reference. There are some ultra-low phase noise OCXOs on the market but these are generally very expensive (some of them are more expensive than ERASynth itself). ERASynth uses a multiple loop architecture to minimize the phase noise without breaking the bank. More details about ERASynth’s architecture may be found on the campaign page above.

Q: Can you give some example applications where I can take advantage of ERASynth?

A: ERASynth can be used just like any bench-top signal generator. Some of the many applications can be listed as:

• Stimulus source for general purpose RF testing: ERASynth can be used to conduct general purpose RF testing such as gain, noise figure, IMD, P1dB, etc.. We will demonstrate measurements of gain and noise figure in one of upcoming campaign updates.
• LO source for down-conversion or up-conversion: Since ERASynth can provide up to +15 dBm RF output level, it is an ideal LO source to drive most of the commercially available mixers. A wideband superheterodyne RF receiver can be easily implemented using ERASynth as the tuning LO thanks to its ultra wide-band RF output range (250kHz to 15GHz). We will demonstrate an example DC to 6 GHz receiver implementation using ERASynth as the tuning LO in one of upcoming campaign updates.
• Clock source for data converters: ERASynth can be used to clock almost any ADC or DAC in existence today. As converter speeds go up in frequency and resolution, clock jitter is becoming more and more important. Design Note 1013 by Linear Technology is an excellent tutorial about the effect of clock jitter on high speed ADCs. ERASynth’s jitter performance (183fs at 10GHz) meets requirements of state-of-the-art giga-sample converters.
• Test signal source for software defined radio (SDR): If you are looking for a low-cost test signal source for your SDR receiver, look no further. ERASynth can do this task perfectly with its blazing fast lock-time (typical 100µs).

Q: Can you give more information on the current revision of the ERASynth? What are the differences between current revision and the upcoming one?

A: ERASynth rev2 is the current revision. We obtained almost all of the data shown on the campaign page by testing the rev2 board. Rev3 is the upcoming board, it will feature a newly release PLL that has an incredible phase noise floor. We will also add an OCXO to rev3 board.

Q: Where can I find the source codes? What is the license?

A: We will make the sources available on Git-Hub once the campaign ends. We haven’t decided on the license yet.