FixedSine

This generator provides a pure sine signal with very little drift and phase noise. It sacrifices flexibility for stability, compactness and simplicity.

The generator can be used with any square wave oscillator from the series AQO 7050 by Auris. Refer to the Bürklin catalogue for a list of available frequencies.

The resistors and inductors of the filter have to be adapted to the specific operation frequency. Refer to table 1 for values known to work. The filter design tool hosted at the university of York, UK is recommended to determine reasonable values from scratch.

A generator configured for 20.00 MHz was characterized:

• frequency drift integrated over a few minutes is less than $1\times 10^{-8}$.
• frequency drift integrated over approximately one second is less than $1\times 10^{-9}$.
• according to the manufacturer the jitter of the oscillator is below 1 ps.

• The project was started in July 2015
• The first prototype was operational in August 2015

About ten devices are in use at Mg.

Nandan Jha

Mg

An integrated quartz oscillator provides ​a stable ​square wave signal. A passive four pole LC filter removes the higher harmonics ​to render a near perfect sine waveform. An amplifier is used on output to increase the amplitude and the ability to drive low impedance loads.

• The schematic im PDF-Format
• The source of the schematic can be found on the download page of the wiki.

• Size of the PCB: 40.5 x 40.5 mm
• Supply: JAE IL-G, 3Pin, +15 V, GND, -15 V
• Input: none
• Output: SMA
• Displays: none
• PDF of the layout: fixedsine_layout_v1.1.pdfDer Bestückungsdruck
• Bill of materials: fixedsine_v1.1_koll.pdf, fixedsine_v1.1_koll.xls
• A zip of the gerber files for pcb production
• The source of the layout in geda format is available at the download page of the wiki.

Layout (top view)

Layout (bottom view)

Hammond 1590LLBK

Mounting holes of the generator and connectors are compatible with the design of the photodiode amplifier PD-ac-dc.

The oscillator should oscillate right out of the box.

When produced as a mini series of 60, the price for the PCB drops to 5.20 € per piece.

(Icons: : nope, : in the works, : done in the schematic, not yet in layout, : done)

1. Add a 1 nF capacitor in parallel to R5. This helps get rid of offset voltages (WTF?)
2. Use AD817 op-amp due to its fast slew rate. C19 and C21 are not needed for this op-amp.
3. Opamps aree borderline fast enough Better use MMICs in the next version. E.g. ERA-8, or similar.
4. A polygon on top is not connected to ground.
5. Ground should be done more properly
6. Diode D3 is drawn in the wrong direction in the layout