def __init__(self, options, queue):
		gr.top_block.__init__(self)

		if options.filename is not None:
			self.fs = gr.file_source(gr.sizeof_gr_complex, options.filename)
			self.rate = options.rate

		else:
			self.u = uhd.usrp_source(options.addr,
									 io_type=uhd.io_type.COMPLEX_FLOAT32,
									 num_channels=1)

			if options.subdev is not None:
				self.u.set_subdev_spec(options.subdev, 0)