Red Pitaya - 4-Channel Measurements

STEMlab 125-14 4-Input

STEMlab 125-14 4 Inputs is based on STEMlab 125-14 board, but instead of 2 inputs and 2 output channels offers 4 Input channels that with improved performance and it is based on the Xilinx ZYNQ 7020 SoC processor.

Red Pitaya 4Ch input

STEMlab 125-14 4-Input is a single-board RF signal acquisition platform that offers the same general hardware features as STEMlab 125-14. The main differences/benefits are that:

There are 4 analog input channels @ 125MSPS & 14 bits (instead of 2 inputs and 2 outputs).

RF inputs come with better performance (less cross-talk, noise, and distortions).

ZYNQ 7020 (bigger FPGA that offers more processing capabilities and more digital IO pins available on the extension connector).

Switching between internal and external clocks can be done using a jumper or control signal on the extension connector.

The internal ADC clock can be locked to an external reference clock via an extension connector (this feature is optional at the moment).

Technical specifications

Basics

Processor	DUAL CORE ARM CORTEX A9
FPGA	FPGA Xilinx Zynq 7020 SOC
RAM	512 MB (4 Gb)
System memory	Micro SD up to 32 GB
Console connection	Micro USB
Power connector	Micro USB
Power consumption	5 V, 2 A max

Connectivity

Ethernet	1 Gbit
USB	USB 2.0
WIFI	optional, requires WIFI dongle

RF Inputs

RF input channels	4
Sample rate	125 MS/s
ADC resolution	14 bit
Input impedance	1 MOhm / 10 pF
Full scale voltage range	±1 V (LV) and ±20 V (HV)
Input coupling	DC
Absolute max. Input voltage range	30 V
Input ESD protection	Yes
Overload protection	Protection diodes
Bandwidth	DC - 60 MHz

Extension Connector

Digital IOs	20
Analog inputs	4
Analog inputs voltage range	0-3.5 V
Sample rate	100 kS/s
Resolution	12 bit
Analog outputs	4
Analog outputs voltage range	0-1.8 V
Communication interfaces	I2C, SPI, UART
Available voltages	+5 V, +3.3 V, -4 V
external ADC clock	yes

Synchronization

Trigger input	Through extension connector
Daisy chain connection	Over SATA connection (up to 500 Mbps)
Ref. clock input	N/A

Software

Dedicated apps have been specially developed for this hardware model because of the different hardware configuration. Depicted in the picture above are the main menu, the Spectrum analyzer app with 4 traces and also the Oscilloscope.

Also this hardware model can be controlled via the SCPI protocol from C, Phyton, LABview or Matlab. More documentation can be found here: SCPI

FPGA build: FPGA

Source Code: all the Red Pitaya available code can be found here.