Transcript S.N.A.T.
Network Analyzer Terminal Scalar Network Analyzer
Dave Collins – AD7JT George Heron – N2APB
Poor Ham’s Scalar Network Analyzer (PHSNA)
With Network Analyzer Terminal (NAT)
TERMINAL (NAT)
POWER READINGS (dB)
< SERIAL INTERFACE >
SCAN PARAMETERS
LOGARITHMIC RF POWER METER (AD8307)
POWER LEVEL RF OUT
ARDUINO-BASED MICROCONTROLLER DEVICE UNDER TEST (DUT)
FREQ RF IN
DIGITALLY CONTROLLED SIGNAL GENERATOR (AD9850/51) https://groups.yahoo.com/neo/groups/PHSNA/info
Features
• Handheld graphic terminal for display and control of the PHSNA • 3.2”, 240 x 320, 16-bit color graphic LCD display & touch panel • User-friendly operator interface • Field upgradable firmware • Serial port connection to PHSNA (digital UART 3.3V) • Keyboard input for control of SSNA menu system • 32KB EEPROM for persistent storage (settings and options) • 14 Macros (in EEPROM) for storing operating parameters • PLX-DAQ (Excel) mode for test automation and PHSNA compat.
• Compatible with standard and enhanced PHSNA f/w versions • Simplified calibration (no curve fitting required) • Measurement & Plot Capabilities (v1.0):
- Testing and evaluating filters - Measuring crystal parameters - Return Loss Measurement - VSWR and antenna tuning - Continuous/repeated operation options
• SD Card mass storage up to 1 GB provides:
- FAT16 file system compatibility - Subdirectory support for easy file management - Data spooling and playback - Calibration data storage and reloading - Direct data exchange with Windows and Linux apps - Easy and efficient firmware upgrades - DOS –like commands to manage and playback data files
Specifications
PCB:
4.47" x 3.31"
Enclosure:
4.82" x 3.77" x 1.39"
Data rates:
1.2 to 19.2 kbaud
Power:
12V DC @ 120ma (typ) (330ma for NACT with DDS-60)
Weight:
7 oz (approx)
Display module - under $20 on eBay:
240 x 320 Pixel (QVGA), 16 bit color, 3.2” LCD SSD1289 display controller Resistive touch screen with ADS7843 controller SD Card socket Pads and interconnect for serial (SPI) EEPROM Single, 40-pin interface connector
Basic NAT Block Diagram
(Versions 1 and 2)
Menu Mode screen shots
1 ENTER
Enter
PLX Mode screen shots
F1 SPACE
Scroll Lock
DOS Mode screen shots
Escape
touch touch
Y
RF IN
Optional PC Application
< SERIAL INTERFACE >
Scalar Network Analyzer (SNA) DEVICE UNDER TEST (DUT)
RF OUT
NAT-SNA: NAT-Scalar Network Analyzer
Block Diagram (Version 4)
NACT to SNA conversion RF Power Meter by Dick Faust, K9IVB http://www.k9ivb.net/RF_Power_Meter/
Scroll Lock
RF Power Meter Mode Primarily intended for QRP applications Power reading taken about 200 times/second (every 5 ms) 100 dBm range, use attenuators to shift the range DDS used only for calibration Three Power Meters Displayed Current power reading (10-point running average) Average Power (200-point running average) Peak Power (updated every 200 samples)
P Ctrl-G Apply RF
Antenna analysis with Return Loss Bridge (RLB)
RF INPUT (FROM DDS)
50 10T-Bifilar (FT37-43) 50
RESONATING DUT (e.g., antenna)
50
RETURN LOSS (TO RF POWER METER) RETURN LOSS BRIDGE
Antenna analysis with Return Loss Bridge (RLB)
Crystal Characterization & Matching
RF OUT
-3dB Attenuator 9.1
150 9.1
10T-Bifilar (FT37-43)
CRYSTAL SOCKET
10T-Bifilar (FT37-43) -3dB Attenuator 9.1
150 9.1
RF IN CRYSTAL TEST FIXTURE
Crystal Characterization & Matching
(cont.)
Crystal Characterization & Matching
(cont.)
References: http://www.midnightdesignsolutions.com/nat https://groups.yahoo.com/neo/groups/NAT-SNA/info https://groups.yahoo.com/neo/groups/PHSNA/info Dave [email protected]
and George [email protected]
QUESTIONS?
COMMENTS?
CRITIQUES?
Time for a little math Gain ratio = P out /P in Gain (dB) = 10 log(P out /P in ) Gain (dBm) = 10 log(P out /.001) = 10 log(P out x 1000) = 10 (log(P out ) + log(1000)) = 10 log(P out ) + 30 Short circuit gain = 10 log(P in /P in ) = 10 log(1) = 0 for any P in Gain (dBm) = 10 log(P in ) - d where: P in = power meter reading d = short circuit gain reading DDS output level varies with frequency (due to sin(x)/x sampling effect) therefore d is a function of frequency: d(f)