Difference between revisions of "TinySA"

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* [https://store2.rlham.com/shop/catalog/product_info.php?products_id=75243&osCsid=adsqkp0uum898eahocj1marc43 R&L page]
 
* [https://store2.rlham.com/shop/catalog/product_info.php?products_id=75243&osCsid=adsqkp0uum898eahocj1marc43 R&L page]
  
== Attenuators ==
+
* [[RF Attenuators]]
 
 
[[file:Chart_mW_vs_dbM.PNG]]
 
 
 
=== 30 dB Attenuator ===
 
 
 
* [http://leleivre.com/rf_pipad.html Pi Attenuator Calculator]
 
 
 
[[file:Atten30dB_P116-720px.jpg]]
 
 
 
[[file:30dB_Attenuator.PNG]]
 
 
 
* Built
 
** Standard 5% resistor values
 
** R1 = 820 in parallel with 22K = 790.6 ohms
 
** R2 = 2 paralleled 120 Ohm 1/4W resistors paralleled with 470 ohms = 53.2 ohms
 
** Flat from 0-30 MHz
 
** Measured attenuation is flat
 
*** -30.01dB at 1 MHz
 
*** -30.24dB at 30 MHz
 
** Input Impedance - 53.1 ohms, 21.3nF
 
** SWR 1.06
 
** 1/2W max (5VDC max, 0 ohm source)
 
 
 
* NanoVNA scan data
 
 
 
[[file:30dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
 
 
 
[[file:30dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
 
 
 
* LTSPICE Simulation
 
 
 
[[file:LTSPice_30dB.PNG]]
 
 
 
=== 20 dB Attenuator ===
 
 
 
[[file:Atten_20dB_P115-720px.jpg]]
 
 
 
[[file:20dB_Attenuator.PNG]]
 
 
 
* Build
 
** Standard 5% resistor values
 
** R1 = 2 of 510 in parallel also in parallel with 8.2K = 247.3 ohms
 
** R2 = 2 paralleled 150 Ohm 1/2W resistors paralleled with 330 ohms = 61.11 ohms
 
** Flat from 0-30 MHz
 
** Measured attenuation is flat
 
** Input Impedance - tbd ohms, tbd nF
 
** SWR tbd
 
** 1W max (8.6 V max, 0 ohm source)
 
 
 
[[file:20dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
 
 
 
[[file:20dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
 
 
 
* LTSPICE Simulation
 
 
 
[[file:LTSPice_20dB.PNG]]
 
 
 
=== 10 dB Attenuator ===
 
 
 
[[file:Atten_10dB_P115-720px.jpg]]
 
 
 
[[file:10dB_Attenuator.PNG]]
 
 
 
* Build
 
** Standard 5% resistor values
 
** R1 = 2 of 150 in parallel also in parallel with 1.5K = 71.43 ohms (0.3% error)
 
** R2 = 3 of 330 Ohm 1/4W parallel resistors paralleled with 810 ohms = 96.85 ohms (0.62% error)
 
** Flat from 0-30 MHz
 
** Measured attenuation is flat
 
** Input Impedance - tbd ohms, tbd nF
 
** SWR tbd
 
** 3/4W max (9.1 V max, 0 ohm source)
 
 
 
[[file:10dB_Attenuator_NanoVNA_Setup_Curve_900MHz.PNG]]
 
 
 
[[file:10dB_Attenuator_NanoVNA_Data_900MHz.PNG]]
 
 
 
* LTSPICE Simulation
 
 
 
[[file:LTSPice_10dB.PNG]]
 
 
 
=== Attenuator Construction ===
 
 
 
* Single side copper clad PCB
 
** Approx 2"x1"
 
* Clean with steel wool
 
* Solder SMA connectors
 
** Use large alligator clips to hold while soldering
 
** Solder on sides only
 
 
 
[[file:Atten_01_SMAs_720px.jpg]]
 
 
 
* Cut "T" Shaped pads
 
** I used nibbler
 
* Center fits between connector ground pins
 
* Glue down pads with Superglue
 
 
 
[[file:Atten_02_Pads_720px.jpg]]
 
 
 
* Solder center pin with big solder blob
 
** A bit too high for direct contact
 
* Verify raised pad does not short to ground
 
 
 
[[file:Atten_03_Solder CenterPads_720px.jpg]]
 
 
 
* Solder side resistor(s)
 
* Leave room for center resistor(s)
 
 
 
[[file:Atten_04_Solder Side_Resistors_720px.jpg]]
 
 
 
* Measure side resistors from pad to ground
 
* Should match value
 
* Solder center resistor(s)
 
 
 
[[file:Atten_05_Solder Center_Resistors_720px.jpg]]
 
 
 
* Verify no shorts between centers and ground
 
  
 
== Measurements ==
 
== Measurements ==

Revision as of 11:46, 7 September 2021

TinySA.jpg

TinySA - Spectrum Analyzer - Specifications

User interface

  • Display resolution 320*240 pixels
  • Screen diagonal 2.8"
  • 16 bits per RGB pixels
  • Resistive touch control
  • Jog switch control
  • USB serial port control
  • Optional TTL USART port (SW not yet implemented) on the internal PCB
  • Linear power supply to avoid switching noise.

The input/output specification of the tinySA is split over the 4 modes

Low input mode spec

  • Input frequency range from 100kHz to 350MHz
  • Input impedance 50 ohm when input attenuation set to 10dB or more.
  • Selectable manual and automatic input attenuation between 0dB and 31dB in 1 dB steps
  • Absolute maximum input level without attenuation of +10dBm
  • Absolute maximum input power with 30dB attenuation of +20dBm for short period
  • Input Intercept Point of third order modulation products (IIP3) with 0dB attenuation of +15dBm
  • 1dB compression point at +2dBm with 0dB attenuation
  • Power detector resolution of 0.5dB and linearity versus frequency of +/-1dB
  • Absolute power level accuracy after power level calibration of +/- 1dB
  • Lowest discernible signal using a resolution bandwidth of 30kHz of -102dBm
  • Frequency accuracy equal to the selected resolution bandwidth
  • Phase noise of -90dB/Hz at 100kHz offset and -115dB/Hz at 1MHz offset
  • Spur free dynamic range when using a 30kHz resolution bandwidth of 70dB
  • Manually selectable resolution filters of 3, 10, 30, 100, 300, 600kHz. Automatic selection of one of the 57 resolution filters.
  • On screen resolution of 145 or 290 measurement points.
  • Scanning speed of over 1000 points/second using largest resolution filters.
  • Automatic optimization of actual scanning points to ensure coverage of the whole scan range regardless of the chosen resolution bandwidth
  • Spur suppression option for assessing if certain signals are internally generated or actually present in the input signal

High input mode spec

  • Input frequency range from 240MHz to 960MHz
  • As there is no input bandfilter strong signals outside the 240MHz to 960MHz range can cause distortion of the in band signals
  • Absolute maximum input level without attenuation of +10dBm
  • Input Intercept Point of third order modulation products (IIP3) of -5dBm
  • 1dB compression point at -6dBm with 0dB attenuation
  • Power detector resolution of 0.5dB and linearity versus frequency of +/-1dB
  • Absolute power level accuracy after power level calibration of +/- 1dB
  • Lowest discernible signal using a resolution bandwidth of 30kHz of -115dBm
  • Frequency accuracy equal to the selected resolution bandwidth
  • Spur free dynamic range when using a 30kHz resolution bandwidth of 50dB
  • Selectable (automatic and manual) resolution filters of 3, 10, 30, 100, 300 and 600kHz
  • Optional 25dB to 40dB frequency dependent input attenuator. The power level error with this attenuator activated increases to +/- 15dB
  • On screen resolution of 145 or 290 measurement points.
  • Scanning speed of over 1000 points/second using largest resolution filters.
  • Automatic optimization of actual scanning points to ensure coverage of the whole scan range regardless of the chosen resolution bandwidth

Low output mode spec

  • Sinus output with harmonics below -40dB of fundamental
  • Output frequency range from 100kHz to 350MHz
  • Output level selectable in 1dB steps between -76dBm and -6dBm
  • Optional AM, narrow FM and wide FM modulation or slow sweep over selectable frequency span

High output mode spec

  • Square wave output
  • Output frequency range from 240MHz to 960MHz
  • Output level selectable in variable increments between -38dBm and +13dBm
  • Optional narrow FM and wide FM modulation or slow sweep over selectable frequency span

Reference generator spec

  • Optional square wave output with fundamental at -25dBm connected to high input/output
  • Frequency can be set to 1MHz, 2MHz, 4MHz, 10MHz, 15MHz or 30MHz.

Battery spec

  • Charging time max 1 hour on 500mA minimum USB port or USB charger
  • Operation on fully charged battery for at least 2 hours
  • Maximum input level
    • 0 dBm = 1 mW
    • dBm = 10*LOG(milliwatts)
    • -10 dBm = 0.1 mW
    • +10dBm = 10 mW
    • +20dBm = 1000 mW
  • 3.3V at 50 Ohm = 0.2178W
    • 217.8 mW = 23.4 dBm

References

Measurements

No Stimulus

  • 50 Ohm terminator on Low port

Tiny-SA App v1.1.19.20.PNG

VFO-001

VFO-001 P132-720px.jpg

  • VFO-001
  • Set to 20 MHz
  • 3.3V square wave drive
  • Rich odd harmonic content
  • Lots of other noise
  • Using 20 dB attenuator (from above)
  • 1-301 MHz

VFO-002 20dB 001.PNG

Videos