flowchart: measure input sample rate via "Probe Rate" block instead of manually counting samples in serial source block

epy_block_0.py

@@ -1,5 +1,3 @@
-import time
-
 import gnuradio
 import numpy
 import serial
@@ -16,8 +14,6 @@ class ArduinoAnalogReadings(gnuradio.gr.sync_block):
             port=port, baudrate=baud_rate, bytesize=serial.EIGHTBITS, timeout=timeout
         )
         self._buffer_max_length = buffer_max_length
-        self._samples_counter = 0
-        self._sample_rate_report_timestamp = None
 
     def work(self, input_items, output_items):
         # pylint: disable=unused-argument
@@ -28,15 +24,4 @@ class ArduinoAnalogReadings(gnuradio.gr.sync_block):
         buffer_samples_count = len(buffer) // 2
         output_items[0][:buffer_samples_count] = numpy.frombuffer(buffer, dtype=">u2")
         assert output_items[0][:buffer_samples_count].max() < 1024, "lost sync?"
-        self._samples_counter += buffer_samples_count
-        current_timestamp = time.time()
-        if not self._sample_rate_report_timestamp:
-            self._sample_rate_report_timestamp = current_timestamp
-        elif (current_timestamp - self._sample_rate_report_timestamp) > 8:
-            sample_rate_hz = self._samples_counter / (
-                current_timestamp - self._sample_rate_report_timestamp
-            )
-            print(f"{sample_rate_hz:.01f} Hz")
-            self._samples_counter = 0
-            self._sample_rate_report_timestamp = current_timestamp
         return buffer_samples_count

scope.grc

@@ -134,6 +134,19 @@ blocks:
     coordinate: [1116, 324]
     rotation: 0
     state: enabled
+- name: blocks_message_debug_0
+  id: blocks_message_debug
+  parameters:
+    affinity: ''
+    alias: ''
+    comment: ''
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [991, 817]
+    rotation: 0
+    state: true
 - name: blocks_multiply_const_vxx_0
   id: blocks_multiply_const_vxx
   parameters:
@@ -152,6 +165,25 @@ blocks:
     coordinate: [816, 324]
     rotation: 0
     state: enabled
+- name: blocks_probe_rate_0
+  id: blocks_probe_rate
+  parameters:
+    affinity: ''
+    alias: ''
+    alpha: '0.15'
+    comment: ''
+    maxoutbuf: '0'
+    minoutbuf: '0'
+    mintime: '10000.0'
+    type: short
+    vlen: '1'
+  states:
+    bus_sink: false
+    bus_source: false
+    bus_structure: null
+    coordinate: [391, 781]
+    rotation: 0
+    state: true
 - name: blocks_short_to_float_0
   id: blocks_short_to_float
   parameters:
@@ -172,29 +204,19 @@ blocks:
 - name: epy_block_0
   id: epy_block
   parameters:
-    _source_code: "import time\n\nimport gnuradio\nimport numpy\nimport serial\n\n\
-      \nclass ArduinoAnalogReadings(gnuradio.gr.sync_block):\n    def __init__(\n\
-      \        self, port=\"/dev/ttyUSB0\", baud_rate=115200, buffer_max_length=10,\
+    _source_code: "import gnuradio\nimport numpy\nimport serial\n\n\nclass ArduinoAnalogReadings(gnuradio.gr.sync_block):\n\
+      \    def __init__(\n        self, port=\"/dev/ttyUSB0\", baud_rate=115200, buffer_max_length=10,\
       \ timeout=2\n    ):\n        gnuradio.gr.sync_block.__init__(\n            self,\
       \ name=\"Arduino Analog Readings\", in_sig=None, out_sig=[numpy.int16]\n   \
       \     )\n        self._serial_port = serial.Serial(\n            port=port,\
       \ baudrate=baud_rate, bytesize=serial.EIGHTBITS, timeout=timeout\n        )\n\
-      \        self._buffer_max_length = buffer_max_length\n        self._samples_counter\
-      \ = 0\n        self._sample_rate_report_timestamp = None\n\n    def work(self,\
-      \ input_items, output_items):\n        # pylint: disable=unused-argument\n \
-      \       buffer = self._serial_port.read(\n            2 * min(len(output_items[0]),\
-      \ self._buffer_max_length)\n        )\n        assert len(buffer) % 2 == 0\n\
-      \        buffer_samples_count = len(buffer) // 2\n        output_items[0][:buffer_samples_count]\
-      \ = numpy.frombuffer(buffer, dtype=\">u2\")\n        assert output_items[0][:buffer_samples_count].max()\
-      \ < 1024, \"lost sync?\"\n        self._samples_counter += buffer_samples_count\n\
-      \        current_timestamp = time.time()\n        if not self._sample_rate_report_timestamp:\n\
-      \            self._sample_rate_report_timestamp = current_timestamp\n      \
-      \  elif (current_timestamp - self._sample_rate_report_timestamp) > 8:\n    \
-      \        sample_rate_hz = self._samples_counter / (\n                current_timestamp\
-      \ - self._sample_rate_report_timestamp\n            )\n            print(f\"\
-      {sample_rate_hz:.01f} Hz\")\n            self._samples_counter = 0\n       \
-      \     self._sample_rate_report_timestamp = current_timestamp\n        return\
-      \ buffer_samples_count\n"
+      \        self._buffer_max_length = buffer_max_length\n\n    def work(self, input_items,\
+      \ output_items):\n        # pylint: disable=unused-argument\n        buffer\
+      \ = self._serial_port.read(\n            2 * min(len(output_items[0]), self._buffer_max_length)\n\
+      \        )\n        assert len(buffer) % 2 == 0\n        buffer_samples_count\
+      \ = len(buffer) // 2\n        output_items[0][:buffer_samples_count] = numpy.frombuffer(buffer,\
+      \ dtype=\">u2\")\n        assert output_items[0][:buffer_samples_count].max()\
+      \ < 1024, \"lost sync?\"\n        return buffer_samples_count\n"
     affinity: ''
     alias: ''
     baud_rate: '115200'
@@ -619,9 +641,11 @@ connections:
 - [blocks_add_const_vxx_0, '0', qtgui_number_sink_0, '0']
 - [blocks_add_const_vxx_0, '0', qtgui_time_sink_x_0, '0']
 - [blocks_multiply_const_vxx_0, '0', blocks_add_const_vxx_0, '0']
+- [blocks_probe_rate_0, rate, blocks_message_debug_0, print]
 - [blocks_short_to_float_0, '0', blocks_multiply_const_vxx_0, '0']
 - [blocks_short_to_float_0, '0', qtgui_freq_sink_x_0, '0']
 - [blocks_short_to_float_0, '0', qtgui_time_sink_x_0_0, '0']
+- [epy_block_0, '0', blocks_probe_rate_0, '0']
 - [epy_block_0, '0', blocks_short_to_float_0, '0']
 - [epy_block_0, '0', qtgui_number_sink_0_0, '0']