- Category: Hardware
- Published on Thursday, 01 January 2015 05:08
- Written by 4Z5LV
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AFEDRI SDR-USB-HS VHF/SHF Features
● 100 kHz to 35.00MHz and 35MHz to 1700MHz continuous frequency range
● Direct RF sampling
● DDC - Digital Down-Conversion
● 12- bit 70.656 MSPS A/D conversion
● Up to 0.92MHz recording and processing bandwidth
● Waterfall display functions, when used with appropriate software
● Recording and playback, when used with appropriate software
● Sensitivity - MDS -133 dBm at 500Hz bandwidth (0.1MHz - 30MHz)
● Sensitivity - MDS -143 dBm at 500Hz bandwidth (144MHz and 435MHz)
● USB 2.0 (High Speed) interface
● Compatible with: Linrad, websdr, Winrad, HDSDR, Studio1, SDR-Console v.2
● Powered from USB
● Dimensions 120mm deep x 78mm wide x 27mm high
● Low cost, starting from - $159 - ( without box, Short Wave only assembly), 179$ (without box, for SW + VHF/SHF assembly), 229$ (in box, for SW + VHF/SHF assembly),
see all available options on ordering page*
AFEDRI SDR-USB-HS (VHF/SHF) it is direct sampling Software Defined Receiver (see picture below)
AFEDRI SDR-USB-HS (VHF/SHF) has next parameters:
0.1MHz-35MHz and 35MHz - 1700Mhz (for VHF/SHF versions - separate antenna connector for each band)
~10dB (for 1MHz-70Mhz range)*
~4dB (for 100Mhz-500Mhz)*
~8dB ( up to 1000Mhz)*
~10dB (on 1296MHz band)
*input VGA (Variable Gain Amplifier) is tuned to maximum Gain
Output data format: two 16-bit I/Q channels
Maximum Receiving bandwidth:
BW = up to 920kHz (for 981333 Hz sample rate) - (in MSD mode) *
* In USB Audio mode with Windows OS the maximal sample rate can be limited to 96Khz.
RF ADC sampling rate: 70.656MHz
Power Supply Voltage: 5V (supplied from USB bus)
Power Supply current:
~ 410mA (in 0.1MHz-30Mhz frequency range)
~ 550mA (in 40MHz-1700Mhz frequency range)
The Newest High-Speed AFEDRI SDR-USB-HS (VHF/SHF) revision
This SDR is designed to be connected to Personal Computer (PC) by High Speed USB link and send to PC two quadrature channels I/Q with sample rate up to ~981k samples per second 16-bit each channel for latest revision on SDR design.
From PC side of view, the AFEDRI SDR-USB-HS can be configured to work in two alternative modes (to keep maximal software compatibility):
1. USB MSD (Mass Storage Device - USB Hard Disk emulation), that contains two USB functions:
2. USB Compisite Device, that contains two USB functions:
- Generic USB Audio device - to transfer baseband I/Q signal, as audio stereo stream
- USB HID device - used to control AFEDRI SDR
The SDR doesn't need any additional driver installation on most of Operational Systems (OS) used on PC today it was successfully tested under next OS Windows XP SP2, Windows Vista 32 bit, Windows 7 32/64 bit, Linux .
The SDR compatible and working with PC SDR software that can work with PC Sound Card device or can use ExtIO plug-in, like HDSDR, Studio1, Winrad (and its different clones), Linrad, SDR Console v.2 etc...
AFEDRI SDR-USB-HS (like other AFEDRI SDRs) is based on AFEDRI8201 integrated circuit, it is Analog Front End (AFE) from Texas Instrument Company (this part obsolete now, but can be found on the market).
The target was - to use AFEDRI8201 as direct sampling receiver and connect it to PC trough USB interface. From PC’s “point of view” the SDR is looking like usual USB MSD (hard disk) or USB Audio Device, that don’t need any additional driver and bring to PC two 16-bit baseband (I and Q) channels at up to 981kHz sample rate. And this SDR can be used with existing SDR software like Linrad or/and Winrad (or any of Winrad 1.32 branches, like HDSDR), running under Windows and/or Linux OS.
This SDR model is good choice for using under Linux OS with WEBSDR server.
Please see the picture below:
There is short block diagram description:
LPF - Low Pass Filter, is used as anti-aliasing filter for from DC to ~30MHz
HPF - High Pass Filter, in SDR with VHF/SHF option it is used to filter signals from ~40Mhz up to ~1700MHz
VGA - Variable Gain Amplifier, it is built using AD8369 IC from Analog Devices, and adjusted in in this design to give amplification/attenuation of input signal from -10dB up to 35dB.
VHF/SHF Receiver Front End - Font End circuit based on R820T2 chip, allow to receive signals in the range 40MHz-1700MHz
Direct Sampling Receiver Front End - i.e Analog Front End is built on AFEDRI8201PBF integrated circuit, it is main device of SDR, that providing Input RF signal ADC sampling, mixing and digital filtering, base-band signal data is outputs through specific serial interface, that very similar to I2S but not 100% compatible, for example used in my design CPU, need external help from CPLD, to accept data incoming data. More information about you can find in datasheet. Please pay attention that this device is obsolete on Texas Instruments, but there is many way to achieve this integrated cuicuits from different sources. And I am sure HAM radio society can use it in their applications. For example I have some quantity of AFEDRI8201PBF in my stock.
CPU - Is Atmel AVR32 architecture microprocessor - AT32UC3A364, it controls both Frond End chips by SPI or I2C control bus, receive processed base-band data from Front End and transfer it to PC using USB link.
RF Switch - used to switch analog signals path to VGA for 0.1Mhz-30Mhz frequency range or to VHF/SHF Front End for 40Mhz-1700Mhz range
Main Clock oscillator - clock oscillator for AFEDRI8201 chip (this oscillator defines also sample rate range and choice)
Ref. Clock TCXO - reference clock oscillator , for R820T2 chip
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