====== FixedSine ====== /* Ein Titelbild: */ /* {{:eigenbau:fixedsine:BILDNAME.jpg?300|}} */ ==== Function ==== This generator provides a pure sine signal with very little drift and phase noise. It sacrifices flexibility for stability, compactness and simplicity. ==== Options and Alternatives ==== The generator can be used with any square wave oscillator from the series [[https://www.buerklin.com/datenblaetter/D108150_TD(1).pdf?ch=2672|AQO 7050]] by [[http://www.auris-gmbh.de|Auris]]. Refer to the [[https://​www.buerklin.com/​de/​katalog/​SMD-Quarzoszillatoren-CMOS-TTL-kompatibel-Typ-Auris-AQO7050-D633000.html|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 {{ref>filtervalues}} for values known to work. The [[http://www-users.cs.york.ac.uk/~fisher/lcfilter/|filter design tool]] hosted at the university of York, UK is recommended to determine reasonable values from scratch. ^ Freq. ^ R3 ^ L3 ^ C14 ^ L4 ^ C16 ^ R4 ^ type ^ | 16.9 MHz | 50 Ω | 1.5μH | 150 pF | 2.2 μH | 100 pF | 300 Ω | chebychev |
Filter values known to work for specific frequencies
==== Performance ==== 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. ==== Timeline ==== * The project was started in July 2015 * The first prototype was operational in August 2015 ==== Status ==== About ten devices are in use at Mg. ==== Developer ==== Nandan Jha ==== User ==== Mg ==== Principle of Operation ==== 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. ==== Schematic ==== * The {{:eigenbau:fixedsine:fixedsine_schematic_v1.1.pdf|schematic}} im PDF-Format * The source of the schematic can be found on the [[:eigenbau:src:sourcen#fixedsine|download page]] of the wiki. ==== Layout ==== * 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: {{:eigenbau:fixedsine:fixedsine_layout_v1.1.pdf}}Der Bestückungsdruck * Bill of materials: {{:eigenbau:fixedsine:fixedsine_v1.1_koll.pdf}}, {{:eigenbau:fixedsine:fixedsine_v1.1_koll.xls}} * A {{:eigenbau:fixedsine:gerberdaten_fixedsine_v1.zip|zip of the gerber files}} for pcb production * The source of the layout in geda format is available at the [[:eigenbau:src:sourcen#fixedsine|download page of the wiki]]. [{{:eigenbau:fixedsine:fixedsine_layout_v1.1.png?400|Layout (top view)}}] [{{:eigenbau:fixedsine:fixedsine_layout_bottom_v1.1.png?400|Layout (bottom view)}}] ==== Enclosing ==== [[http://www.hammondmfg.com/pdf/1590LB.pdf|Hammond 1590LLBK]] Mounting holes of the generator and connectors are compatible with the design of the photodiode amplifier [[eigenbau:photodiode:photodiodenverstaerker_20_mhz:start|PD-ac-dc]]. ==== Test ==== The oscillator should oscillate right out of the box. ==== Images ==== /* Photos vom Gerät. Wenn möglich und sinnvoll Nahaufnahmen von der Platine. Die Bilder sollten in einem Unterordner "bilder" zum Projekt untergebracht sein. Beipiel für den Aufruf einer Bildergalerie: {{gallery>:eigenbau:fixedsine:bilder?lightbox&showname&4 }} */ ==== Cost ==== ^ item ^ amount ^ value ^ total ^ remarks ^ | 4-layer PCB | 1x | 24.50 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | 1/4 of 95.43 EUR (Basista-Prototyping) | | enclosing | 1x | 8.20 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | Hammond 1590LLBBK | | SMA connector | 1x | 1.60 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | | | JAE IL-G connector, 3 pin | 1x | 0.30 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | | | voltage regulator | 2x | 0.20 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | SOT89 | | 100 µH inductor | 2x | 0.30 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | | | 10 µF tantalum cap | 3x | 0.80 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | | | HF inductor | 2x | 0.50 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | Epcos B82498F | | oscillator | 1x | 2.30 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | Auris AQO-7050 | | opamp AD817 | 1x | 6.55 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | fast, high slew rate | | resistors, caps, diodes | 25x | 0.02 € | ~~=round(cell(1,row())*cell(2,row());2)~~ € | all parts sized 0805 | | [[:eigenbau:Verschnitt|off-cuts]] | 5.00 € ||| | ^ total overall: ||^ ~~=round(sum(range(3,1,3,row()-1));2)~~ € | | When produced as a mini series of 60, the price for the PCB drops to 5.20 € per piece. ==== Todo ==== (Icons: :no:: nope, :Ok:: in the works, :ok:: done in the schematic, not yet in layout, :OK:: done) - Add a 1 nF capacitor in parallel to R5. This helps get rid of offset voltages (WTF?) - Use AD817 op-amp due to its fast slew rate. C19 and C21 are not needed for this op-amp. - Opamps aree borderline fast enough --> Better use MMICs in the next version. E.g. ERA-8, or similar. - A polygon on top is not connected to ground. - Ground should be done more properly - Diode D3 is drawn in the wrong direction in the layout