The SinCos Interpolator reads the analog signals from (e.g. Heidenhain) linear scales and converts them into digital quadrature signals. The design is based on the iC-NV chip by iC-Haus. This board performs essentially the same function as Heidenhain "EXE" converters. The design was created for Heidenhain LS 403 linear scales with 11 uA peak-to-peak signals. Through different component values and solder jumper configuration, it should be usable also for other linear scales and similar transducers.

As of 2023-08-22, the version 1.3 design currently found here is yet untested. Version 1.0 tested appeared to be otherwise working, but had power/ground swapped for the MC3487DX IC. A RJ45 jack for the encoder side has also been added since version 1.0.

• Converts analog sine/cosine signals into digital quadrature outputs
• Interpolation factor selectable by solder jumpers
• Suitable for different type of input signals by resistor selection and solder jumper configuration
• Single ended or differential outputs (the latter with additional MC3487DX IC)
• Support for index/reference signal
• Normal screw terminal blocks with 5.08 mm raster for connections
• Optionally shielded RJ45 connectors for inputs and/or outputs
• Reverse polarity protection
• Overvoltage protection through crowbar circuit
• Using mainly through hole component for ease of soldering
• Two layer board with components on top side only

By component values and solder jumper configuration, the board can be adapted to different type of transducers. For 11 uA peak-to-peak transducers, resistors R11, R12, R21 and R22 should have a 25 kOhm resistance and VREF jumpers JP11 and JP21 should be shorted by soldering. Jumper JP2/SG1 should be soldered "LO" (circuit ground) and JP1/SG0 should be left open to allow signal amplitues of up to 1 Vpp. Jumper JP5/ROT can be soldered "LO" unless some specific phase behaviour is required. Jumpers JP4/SF1 and JP3/SF0 are both left open for an interpolation factor of 5. With the 20 um periodicity of the LS 402 linear scales, this gives an output resolution of 1 um (provided the flanks of the A/B signals are "counted"). Jumper JP6/RCLK should be soldered short unless minimun transition distance needs to be adjusted. For all suggestions given in this paragraph, the iC-NV datasheet is not exceptionally clear, and you may want to do you own interpretation.

Single ended or differential outputs are selected by jumpers JP12-JP13, JP22-JP23 and JP32-JP33. In the open state, differential outputs are used, which also requires the board to be populated with the MC3487DX IC. In case single ended signals are preferred, the MC3487DX is left out and the aforementioned jumpers are soldered short. This connects the output from the iC-NV directly to the "positive" output signal terminals and the "negative" signal terminals are tied to ground.

One of the ground terminals was separated out as shield in version 1.3. This can be connected through (wihtout connecting it to ground) by soldering short JP8. Both input/output ends can also be tied to ground individually through JP7/JP9.