added scanraw example

LC-Linkous · LC-Linkous · commit c495e9d5d296 · 2025-06-08T22:54:03.000-04:00
diff --git a/examples/plotting_scanraw.py b/examples/plotting_scanraw.py
@@ -0,0 +1,99 @@
+## This is a comparison of SCAN and SCANRAW to work out some errors in the decode process
+# given that the tinySA is still running during the read, we don't expect SCAN and SCANRAW 
+# to be exactly the same, but they should be relatively similar values when SCANRAW is decoded
+
+
+# import tinySA library
+# (NOTE: check library path relative to script path)
+from src.tinySA_python import tinySA 
+
+
+# imports FOR THE EXAMPLE
+import numpy as np
+import matplotlib.pyplot as plt
+import struct
+
+def convert_data_to_arrays(start, stop, pts, data):
+    # FOR PLOTTING
+    # using the start and stop frequencies, and the number of points, 
+
+    freq_arr = np.linspace(start, stop, pts) # note that the decimals might go out to many places. 
+                                                # you can truncate this because its only used 
+                                                # for plotting in this example
+
+    # As of the Jan. 2024 build in some data returned with SWEEP or SCAN calls there is error data.  
+    # https://groups.io/g/tinysa/topic/tinasa_ultra_sweep_command/104194367  
+    # this shows up as "-:.000000e+01".
+    # TEMP fix - replace the colon character with a -10. This puts the 'filled in' points around the noise floor.
+    # more advanced filtering should be applied for actual analysis.
+    data1 =bytearray(data.replace(b"-:.0", b"-10.0"))
+    
+    # get both values in each row returned (for reference)
+    #data_arr = [list(map(float, line.split())) for line in data.decode('utf-8').split('\n') if line.strip()] 
+   
+    # get first value in each returned row
+    data_arr = [float(line.split()[0]) for line in data1.decode('utf-8').split('\n') if line.strip()]
+
+    return freq_arr, data_arr
+
+
+# create a new tinySA object    
+tsa = tinySA()
+# attempt to autoconnect
+found_bool, connected_bool = tsa.autoconnect()
+
+# if port closed, then return error message
+if connected_bool == False:
+    print("ERROR: could not connect to port")
+else: # if port found and connected, then complete task(s) and disconnect
+    # detailed messages turned on
+    tsa.set_verbose(True) 
+
+    # set scan values
+    start = int(150e6)   # 150 MHz
+    stop = int(500e6)    # 500 MHz
+    pts = 450            # for tinySA Ultra
+    outmask = 2     # get measured data (y axis)
+    # scan raw call - reads until end of stream
+    # this CAN be run in a loop. the limiting factor is time to plot. 
+
+    # SCAN
+    scan_data_bytes = tsa.scan(start, stop, pts, outmask)
+
+    # SCAN RAW
+    scanraw_data_bytes = tsa.scan_raw(start, stop, pts, outmask)
+
+    # disconnect because we don't need the tinySA to process data
+    tsa.disconnect()
+
+    # process the SCAN data (this is already in dBm)
+    # convert data to 2 arrays for X and Y
+    freq_arr, data_arr = convert_data_to_arrays(start, stop, pts, scan_data_bytes)
+
+    # PROCESS SCANRAW into an array & reuse the FREQ_ARR value
+    # remove the intro curly brace ({) 
+    bin_scanraw = scanraw_data_bytes[1:] #skip the first char because it's the raminaing curly brace
+    # use struct.unpack() because of the repeating pattern
+        # <: indicates little-endian byte order, meaning the least significant byte is stored first
+        # 'xH'*pts: a repetition of the format 'xH' once per point.
+        # 'x': represents a pad byte, which is ignored
+        # 'H': represents an unsigned short integer (2 bytes)
+    processed_scanraw = struct.unpack( '<' + 'xH'*pts, bin_scanraw ) # ignore trailing '}ch> '
+    processed_scanraw = np.array(processed_scanraw, dtype=np.uint16 ).reshape(-1, 1) #unit8 has overflow error
+
+    # CONVERT to dBm Power
+    # take the processed binary data and convert it to dBm. 
+    # The equation is from tinySA.org & official documentation
+    SCALE_FACTOR = 174  # tinySA Basic: 128, tinySA Ultra and newer is 174
+    dBm_data = processed_scanraw / 32 - SCALE_FACTOR
+    print(dBm_data)
+
+    # plot
+    plt.plot(freq_arr, data_arr, label= 'SCAN data')
+    plt.plot(freq_arr, dBm_data, label= 'SCANRAW data')
+    plt.xlabel("frequency (hz)")
+    plt.ylabel("measured data (dBm)")
+    plt.title("tinySA SCAN and SCANRAW data")
+    plt.legend()
+    plt.show()
+
