private void freqSelect_rd_checked(object sender, RoutedEventArgs e)
        {
            RadioButton rdBtn = sender as RadioButton;

            if (highFreq_cb == null || midFreq_cb == null || lowFreq_cb == null)
            {
                return;
            }

            if (rdBtn.Content.ToString() == "高频")
            {
                highFreq_cb.Visibility    = Visibility.Visible;
                midFreq_cb.Visibility     = Visibility.Hidden;
                lowFreq_cb.Visibility     = Visibility.Hidden;
                highFreq_cb.SelectedIndex = 0;
                ProtocolCommands.setSampleRate(0x01, 1);
            }
            else if (rdBtn.Content.ToString() == "中频")
            {
                highFreq_cb.Visibility   = Visibility.Hidden;
                midFreq_cb.Visibility    = Visibility.Visible;
                lowFreq_cb.Visibility    = Visibility.Hidden;
                midFreq_cb.SelectedIndex = 0;
                ProtocolCommands.setSampleRate(0x02, 1);
            }
            else if (rdBtn.Content.ToString() == "低频")
            {
                highFreq_cb.Visibility   = Visibility.Hidden;
                midFreq_cb.Visibility    = Visibility.Hidden;
                lowFreq_cb.Visibility    = Visibility.Visible;
                lowFreq_cb.SelectedIndex = 0;
                ProtocolCommands.setSampleRate(0x03, 1);
            }
        }
        private void sampleRate_low_CB_Changed(object sender, SelectionChangedEventArgs e)
        {
            ComboBox cb = sender as ComboBox;

            if (cb.Visibility == Visibility.Visible)
            {
                ProtocolCommands.setSampleRate(0x03, Convert.ToByte(cb.SelectedIndex + 1));
            }
        }