National Instruments 780710-01 IF Transceiver

The National Instruments 780710-01 or PXIe-5641R is a versatile intermediate frequency (IF) transceiver that integrates an FPGA for customizable signal processing. This device supports both analog input (AI) and analog output (AO) channels. It features two analog input channels with a 14 bit ADC resolution operating at sample rates ranging from 30 MS/s to 100 MS/s. The input channels offer a full scale input range of +8.5 dBm peak at 10 MHz along with a typical maximum input level of +24 dBm to prevent damage.

The analog input of the transceiver is AC coupled with an input impedance of 50 Ω and exhibits an input return loss of less than -15 dB within the 250 kHz to 80 MHz range. This ensures efficient signal transmission with minimal reflection. The IF input channels feature an average noise density of -143 dBm/Hz and a signal to noise ratio greater than 76 dB. The maximum instantaneous bandwidth is limited to 20 MHz that is dictated by the digital downconverter (DDC) within the device. This NI 780710-01’s digital downconverter supports up to six channels per ADC along with a 16-bit resolution for both I and Q data streams. The DDC offers decimation from ÷4 to ÷4,096, and the tuning resolution is set by the ADC clock divided by 232.

The device includes two analog output channels with a 14 bit DAC resolution that are capable of sampling at rates from 30 MS/s to 200 MS/s. These output channels are AC-coupled along with an output impedance of 50 Ω and return loss of less than -15 dB. The outputs can handle a maximum DC bias voltage of 10 V without damage and they exhibit a typical noise density of -153 dBm/Hz. This transceiver's system-level modulation quality is demonstrated by its modulation error ratio (MER), achieving over 57 dB at a 10 MHz carrier. The onboard FPGA, a Xilinx Virtex 5 SX95T, includes 94,208 logic cells and 640 DSP blocks. The module also includes 128 MB of onboard DRAM which supports a theoretical maximum data rate of 1,600 MB/s.