GnuRadio python插值块

Question

我一直在研究Gnuradio tutorials，以了解块是如何制作的。

我正在尝试制作一个插值块（1 个输入：2 个输出），它返回输入值乘以两个输出流中的常数。我已经将它实现为一个类，multiply_out_fff()，它继承自 interp_block

import numpy
from gnuradio import gr

class multiply_out_fff(gr.interp_block):
    """ 
    docstring for block multiply_out_fff
    """
    def __init__(self, multiple):
        gr.interp_block.__init__(self,
            name="multiply_out_fff",
            in_sig=[numpy.float32],
            out_sig=[numpy.float32], interp = 2)
        self.multiple = multiple


    def work(self, input_items, output_items):
        in0 = input_items[0]
        out = output_items[0]

        print("the data coming in: ", in0)
        print("in shape ",in0.shape)

        for i in range(0,len(out)/2):
          out[i] = in0[i] * self.multiple
        for i in range(len(out)/2,len(out)):
          out[i] = in0[i-len(out)] * self.multiple

        print("the data going out: ", out)
        print("out shape ", out.shape)

        return len(output_items[0])

我已经为这个块编写了一个测试，并设法让它通过，但不是我最初认为的工作方式

from gnuradio import gr, gr_unittest
from gnuradio import blocks
from multiply_out_fff import multiply_out_fff

class qa_multiply_out_fff (gr_unittest.TestCase):

    def setUp (self):
        self.tb = gr.top_block ()

    def tearDown (self):
        self.tb = None

    def test_001_t (self):
        # set up fg
        self.data = (0,1,-2,5.5)
        self.expected_result = (0,2,-4,11,0,2,-4,11)

        print("---------testing----------")
        print("test data: ", self.data)

        #make blocks
        self.src = blocks.vector_source_f(self.data)
        self.mult = multiply_out_fff(2)
        self.snk1 = blocks.vector_sink_f()
        self.snk2 = blocks.vector_sink_f()

        #make connections
        self.tb.connect((self.src,0),(self.mult,0))
        self.tb.connect((self.mult,0),(self.snk1,0))
        #self.tb.connect((self.mult,1),(self.snk2,0))
        self.tb.run ()

        self.result_data1 = self.snk1.data()
        #self.result_data2 = self.snk2.data()

        print("The output data: ", self.result_data1)
        print("--------test complete-------------\n")

        # check data
        self.assertFloatTuplesAlmostEqual(self.expected_result, self.result_data1)
        #self.assertFloatTuplesAlmostEqual(self.expected_result, self.result_data2)


if __name__ == '__main__':
    gr_unittest.run(qa_multiply_out_fff, "qa_multiply_out_fff.xml")

运行测试脚本给出：

 ~/gnuradio/gr-tutorial/python$ python qa_multiply_out_fff.py 
---------testing----------
('test data: ', (0, 1, -2, 5.5))
('the data coming in: ', array([ 0. ,  1. , -2. ,  5.5], dtype=float32))
('in shape ', (4,))
('the data going out: ', array([  0.,   2.,  -4.,  11.,   0.,   2.,  -4.,  11.], dtype=float32))
('out shape ', (8,))
('The output data: ', (0.0, 2.0, -4.0, 11.0, 0.0, 2.0, -4.0, 11.0))
--------test complete-------------

.
----------------------------------------------------------------------
Ran 1 test in 0.002s

OK

我很难理解的概念是我的块如何返回数据。现在，它在一个数组中返回两个插值输出流，其长度是输入的两倍。我认为它应该有两个独立的输出数组，并允许我有一个单独的接收器连接到每个输出，就像这样（在测试中注释掉）：

    self.tb.connect((self.mult,0),(self.snk1,0))
    self.tb.connect((self.mult,1),(self.snk2,0))

相反，我的所有数据都流入 snk1。如果我取消注释第二个连接，我会收到一条错误消息，通知我 self.mult 块不能有更多的输出连接。

ValueError: port number 1 exceeds max of 0

如何制作一个插值块，我可以使用它进行多个输出连接？

Answer 1

看起来我误解了“interp”参数，它指定了输入向量长度和输出向量长度之间的比率。为该块创建多个输出的正确方法是将 'out_sig' 参数修改为输出类型列表，如下所示在修改后的 multiply_out_fff 类中。

import numpy
from gnuradio import gr

class multiply_out_fff(gr.interp_block):
    """ 
    docstring for block multiply_out_fff
    """
    def __init__(self, multiple):
        gr.interp_block.__init__(self,
            name="multiply_out_fff",
            in_sig=[numpy.float32],
            out_sig=[numpy.float32,numpy.float32], interp = 1)
        self.multiple = multiple


    def work(self, input_items, output_items):
        in0 = input_items[0]
        out1 = output_items[0]
        out2 = output_items[1]    
#        print("the data coming in: ", in0)
#        print("in shape ",in0.shape)

        for i in range(len(in0)):
          out1[i] = in0[i] * self.multiple

        for i in range(len(in0)):
          out2[i] = in0[i] * self.multiple * 2 

#        print("the data going out: ", out)
#        print("out shape ", out.shape)

        return len(output_items[0])

Gnuradio Reference

Gnuradio - “如果我们想要向量，我们可以将它们定义为 in_sig=[(numpy.float32,4),numpy.float32]。这意味着有两个输入端口，一个用于 4 个浮点数的向量，另一个用于标量。”