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前言

GNU Radio 中没有实现测量两个模块之间的时间测量模块，本文记录一下通过 python block 制作一个很简单的测时 block。

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一、timestamp_sender 模块

使用 python block 做一个发送端时间戳记录模块，并添加下面的代码：

"""
Embedded Python Blocks:Each time this file is saved, GRC will instantiate the first class it finds
to get ports and parameters of your block. The arguments to __init__  will
be the parameters. All of them are required to have default values!
"""import numpy as np
from gnuradio import gr
import time
import numpy as npclass timestamp_sender(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block"""Embedded Python Block example - a simple multiply const"""def __init__(self):  # only default arguments here"""arguments to this function show up as parameters in GRC"""gr.sync_block.__init__(self,name="timestamp_sender",   # will show up in GRCin_sig=None,out_sig=[np.float32])self.kk = 1;# if an attribute with the same name as a parameter is found,# a callback is registered (properties work, too).def work(self, input_items, output_items):# Record the current timestart = np.float32(time.perf_counter())# Output data and the current timestamp (here using a simple value for demonstration)output_items[0][:] = [start for _ in output_items[0]]if self.kk == 1:self.kk = 2;print(f"output_items[0][:] = {output_items[0][:]}");return len(output_items[0])

二、timestamp_receiver 模块

使用 python block 做一个接收端时间戳记录模块，并添加下面的代码：

"""
Embedded Python Blocks:Each time this file is saved, GRC will instantiate the first class it finds
to get ports and parameters of your block. The arguments to __init__  will
be the parameters. All of them are required to have default values!
"""import numpy as np
from gnuradio import gr
import numpy as np  # 导入NumPy库
import timeclass timestamp_receiver(gr.sync_block):  # other base classes are basic_block, decim_block, interp_block"""Embedded Python Block example - a simple multiply const"""def __init__(self):  # only default arguments here"""arguments to this function show up as parameters in GRC"""gr.sync_block.__init__(self,name="timestamp_receiver",   # will show up in GRCin_sig=[np.float32],out_sig=None)# if an attribute with the same name as a parameter is found,# a callback is registered (properties work, too).self.kk = 1def work(self, input_items, output_items):for item in input_items[0]:if item == 0:continueif self.kk == 1:self.kk = 2end = np.float32(time.perf_counter())print(f"input_items[0] = {input_items[0]}")print(f"Received at {end}, interval since sent: {(end - item) * 1000000} Microsecond")return len(input_items[0])

三、测试

按照下图将 block 进行连接：

采样率 32KHz，延时 320 * 5 = 160000 个采样点，大约 5s 的时间

打印信息：

Generating: '/home/gnep/ofdm_usrp/test.py'Executing: /usr/bin/python3 -u /home/gnep/ofdm_usrp/test.pyPress Enter to quit: output_items[0][:] = [7809.57 7809.57 7809.57 ... 7809.57 7809.57 7809.57]
item = 7809.56982421875
input_items[0] = [   0.      0.      0.   ... 7809.57 7809.57 7809.57]
Received at 7814.44189453125, interval since sent: 4872070.3125 Microsecond

可以看到打印信息为 4872070.3125 ，大约为 5s 时间

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