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HK$ 8,860
pledged of HK$ 50,000pledged of HK$ 50,000 goal
3
backers
Funding Unsuccessful
The project's funding goal was not reached on Fri, August 30 2019 11:15 PM UTC +00:00
Last updated August 30, 2019

RF Broadband Shot Noise Generator - 2

An RF Broadband Shot Noise Generator suitable for Software Defined Radios (SDR).

RF Broadband Shot Noise Generator - 2

An RF Broadband Shot Noise Generator suitable for Software Defined Radios (SDR).

HK$ 8,860
pledged of HK$ 50,000pledged of HK$ 50,000 goal
3
backers
Funding Unsuccessful
The project's funding goal was not reached on Fri, August 30 2019 11:15 PM UTC +00:00
Last updated August 30, 2019

About

We are building a RF Broadband Shot Noise Generator. RF broadband noise generators are useful electronic instruments with many applications.

Some of the applications for a broadband RF noise generator are:  


  • Scalar Network Analyzers  
     
  • Filter Response Measurements  
     
  • Satellite Tuning  
     
  • Cellphone Network Tuning  
     
  • Antenna VSWR Measurements  
     
  • Amplifier Noise Measurements  
     
  • Jammers
     

They are frequently used with spectrum analyzers, network analyzers and other instruments. When used in combination with SDRs, they can become a Scalar Network Analyzer.

Here is a short list of some SDRs:


  • Airspy  
     
  • BladeRF  
     
  • HackRF  
     
  • LimeSDR  
     
  • NooElec  
     
  • RTL-SDR  
     
  • USRP  
     

Here we see a noise generator being used with an SDR to tune an antenna.  

Figure 2
Figure 2

Here is an example of a noise generator being used with an SDR to tune a filter.  

Figure 3
Figure 3

The circuit below is an experimental setup testing a zener diode as the noise source followed by two stages of gain into an RTL-SDR. The laptop graph shows the noise floor without power to the circuit.  

Figure 4
Figure 4

This is a screen capture of the above test.  

Figure 5
Figure 5

Power is turned on to produce the noise spectrum.  

Figure 6
Figure 6

This is a screen capture of the above test.  

Figure 7
Figure 7

The noise signal bandwidth of the zener diode is limited and the noise signal strength is not flat. The circuit was modified, shielded and feed into a bladeRF SDR. The limited bandwidth and nonlinear signal strength across the bandwidth is all due to the zener diode. A stripline version with the 24V zener and two stages of gain were feed into a bladeRF SDR as shown below.  

Figure 8
Figure 8

The problem with Zener diodes is the narrow noise bandwidth and Johnson noise after cutoff.  All the circuits I have seen have cutoff frequencies in the Megahertz range.  The one noise circuit I saw used in the Gigahertz range, that had a Zener diode, was actually amplifier noise, which is Johnson noise, and had spectrum distribution problems due to the several stages of amplification. A carbon resistor could have been substituted for the Zener with no affect on the output.

The alternative to Zener diodes is the avalanche diode specifically designed as a RF noise generator which generate SHOT noise.  These devices are difficult to acquire and have very high prices which often exceed the entire cost of all the parts and components needed to build the instrument.

Shot noise, a type of noise which can be modeled by a Poisson statistical process, is temperature and frequency independent, in contrast to Johnson–Nyquist noise, which is proportional to temperature with the spectral density decreasing with increasing frequency.  White noise and Poisson noise sources may be specified in certain types of advanced measurements of network cables, radar, satellite systems, GPS and advanced communications systems where spectral noise power density is critical.  This also applies to jitter, A/D quantum errors and other error statistics in measurement and detection systems.  All military grade jammers use SHOT noise generators.  The field of noise generation and measurement is a highly advance specialty.

Professor Jackson at Jackson Research has discovered a semiconductor that generates RF noise like an avalanche noise diode into the Gigahertz range, but at Zener diode prices.  He has raw laboratory data and now needs to build up a professional grade instrument.

Existing RF Noise Generators

There are at least two cheap noise generators on the Internet. The cheapest one is known to be a waste of money at US$25. The unit generates Johnson noise.  The Zener could be substituted with a carbon resistor with no affect on the output.  The other one has limited bandwidth, high spectrum ripple and low ENR. The inexpensive models have poor performance and bandwidth falling off before 1.7 GHz and are Johnson Noise generators. Professional models can start at around US$3,500 and go up to over US$30,000 and are SHOT noise generators.

Our RF Noise Generator Specifications

  • The bandwidth shall be 40 MHz minimum to 6 GHz. maximum.  
     
  • The target output shall be 0 dBm.  
     
  • The flatness cannot be anticipated, but is hopefully less than 2 dbm over the bandwidth.  
     
  • The spectrum flatness in this design shall be uncompensated.  
     
  • Any requirement for bandwidth flatness compensation shall be met in a subsequent design.  
     
  • The input voltage shall be 5 Vdc. (requires external 5V 2.4A supply not included)  
     
  • The design may require a heat sink which shall be determined on the final PCB.  
     
  • The target price is US$500.  
     

What You Get

This is the proposed case  (150 mm x 64 mm x 37 mm) to enclose the RF Noise Generator. There will be a SMA connector on one end and a power jack on the other end. The RF Noise Generator shall meet the above specifications.  No power supply is included nor are there any cables.

Figure 9
Figure 9

Design and Engineering

John T. Jackson, Jr., MS received his BS Physics from Oregon State University and his MS Electronics from the University of Nevada, Reno. He is the inventor of the "Wide Air Gap Permanent Magnet Motors" (slotless Motor). He has many patents in the field of magnetics. His Masters Degree was in RF Electronic Engineering at the University of Nevada, Reno. He maintains a private research and development laboratory in Hong Kong.  

This phase of the project is complete.

Manufacturing

Our PCBs are fabricated and stuffed in Hong Kong. We have in house hot air soldering stations. These boards will be stuffed by Jackson Research at our facilities in Hong Kong. This instrument is high tech industrial/aerospace grade merchandise.  

Timeline

PCB fabrication takes two weeks from the confirmation of receipt of the funding. Stuffing the boards in our facilities will take an additional four weeks after that. Final assembly and testing takes another two weeks. The entire process from start to finish shall take eight weeks.  

Risks and challenges

Our team, comprised of Silicon Valley aerospace professionals, has decades of design and manufacturing experience. The biggest risk is the availability and lead time on the noise diodes. With that in mind, we see the usual logistical delays which have been calculated into the project time line.

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    JRNS6000 Broadband RF Noise Generator

    We are building a RF Broadband Noise Generator. RF broadband noise generators are useful electronic instruments with many applications. The frequency range is 1 MHz to 6 GHz.

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