- Siemens S65 and C75 LCD info
- Schematic diagrams of some models of DiSEqC-switches
- Front-end TBCE18210WM description
- Front-end TBCE18117IN description
- Front-end Sharp H77G08 (SG492VA-A) description
DiSEqC-Switch DIGITAL Telecom DT-2000
This schematic solution does not use PIN-diodes. Usually PIN-diodes are used for the high frequency commutation, but in this schematic diagram the signals from LNBs are mixed, when more than one LNB will work simultaneously. It is possible if one of ports is faulty (after short circuit for example during hot-connecting). The yellow fields at the diagram define parts, that are not populated in the PCB.
Description of front-end units from analogue satellite receivers
The following front-ends are from old obsolete satellite receivers and they can be used for building an own project.
A dual input front-end with a 3-wire serial interface. The interface is simple, but seems to be non-standard, similar to the SPI-interface. The PLL is LC7215 clocked at 11.16MHz. Reference frequency is selectable from the following range: 1kHz, 5kHz, 9kHz or 10kHz. The prescaler uPB1505 (with division coefficient equal to 128) is on an input of the PLL. The minimum frequency step equals to 128kHz, 640kHz, 1.152MHz or 1.28MHz. FM-demodulator - TDA8012.
This is a front-end controlled via a 2-wire serial interface (the I2C) and is based on a PLL-synthesizer of TSA5055. The pin "ADDR" ("P3" by the datasheet of the IC) defines the logical I2C-address of the PLL-IC. The minimal frequency step equals to 125kHz (if the PLL is clocked at 4MHz). There is an FM-demodulator - TDA8012. This front-end is very good for building an own analogue sat-finder using MCU (AVR, PIC,..).
Sharp H77G08 (SG492VA-A)
The front-end is intended for the using with an external PLL-synthesizer (BU2611 with clock 5.625MHz). Varicaps voltage is 24V. The front-end has a prescaler IC with marking "12079". FM-demodulator - Sharp IX1475PA.