(Click on picture above for a larger version)
ADC: Linear Technology LTC2208
DAC: Analog Devices AD9744
CODEC: TI TLV320AIC23B
FPGA: Altera EP3C25-QFP240 Cyclone III
CPLD: Altera EMP240-QFP100 MAX II
USB: Cypress CY7C68013A FX2
SERDES: TI TLK2701
EEPROM: Microchip 24C128
- Internal encode clock is 125 MHz.
- Board interface is through:
- USB 2.0 or,
- Optic Fiber SFP Module at 2.5 Gbps or,
- Copper Cat6 cable at 2.5 Gbps.
- TI CODEC provides 48/96kHz audio in and audio out
- FPGA can be programmed via USB or Fiber/Copper interface in Fast Parallel Programming mode (byte wide transfers per clock cycle).
- JTAG interface for FPGA and CPLD
- ADC IN
- DAC OUT
- EXT ENCODE IN
- MIC IN
- L&R AMPLIFIED AUDIO OUT
- L&R LINE IN
- L&R LINE OUT
- DC POWER IN
- USB 2.0
- RJ45 (2.5 Gbps serial over copper)
- SFP (2.5 Gbps serial over fiber)
- TTL Level Serial from FX2
- SPI and I2C to RF external RF board
RF Front End/BPF Board:
An external RF board will determine the frequency range and will allow home-brew RF front ends. The QS1RT VERB provides an SPI and I2C bus for controlling the RF front end board.
2.5 Gbps Serial Link:
The other end of the 2.5 Gbps interface will be a PCI and PCI Express board for the PC. This interface board will have a matching TI TLK2701 SERDES, a CYCLONE II EP3C25, a TI CODEC, and a PLX PCI or PCIe-to-local bus interface chip. The two boards can be connected by Cat6 copper or optical fiber through the SFP module interface.
The USB 2.0 interface allows the use of the QS1RT VERB with PC laptops or if the copper/fiber interface is not desired.
The ADC IN and DAC OUT ports are transformer coupled using Minicircuits T1-6T transformers which gives 15 kHz to 300 MHz coverage. The external RF front end board will determine the actual frequency coverage of the system.
I am having good luck with Picolight SFP modules for the fiber interface which cost about $50 each. I have successfully tested the optical interface though 100 meters of fiber.