What are Format S11, Format S21, Channel S11

[Sarah-C]

Is there a doc anywhere about the three "format, format, channel" buttons anywhere?

They're in the 1.2.27 build, but I'm a bit confused about how they flip, and what they're doing.

[Sarah-C]

Nothing yet... I'll keep monitoring!

[Sarah-C]

I noticed in ui.c, that the "channel" button mostly appears to toggle the kind of smith chart it uses - roughly speaking.

Any clearer explanation would be awesome! =)

#define F_S11     0x00
#define F_S21     0x80
static UI_FUNCTION_ADV_CALLBACK(menu_format_acb)
{
  if (current_trace == TRACE_INVALID) return; // Not apply any for invalid traces
  uint16_t format = data & (~F_S21);
  uint16_t channel = data & F_S21 ? 1 : 0;
  if (b) {
    if (trace[current_trace].type == format && trace[current_trace].channel == channel)
      b->icon = BUTTON_ICON_CHECK;
    if (format == TRC_SMITH) {
      uint8_t marker_smith_format = get_smith_format();
      if ((channel == 0 && !S11_SMITH_VALUE(marker_smith_format)) ||
          (channel == 1 && !S21_SMITH_VALUE(marker_smith_format))) return;
      plot_printf(b->label, sizeof(b->label), "%s\n" R_LINK_COLOR "%s", get_trace_typename(TRC_SMITH, marker_smith_format), get_smith_format_names(marker_smith_format));
    }
    else
      b->p1.text = get_trace_typename(format, -1);
    return;
  }

  if (format == TRC_SMITH && trace[current_trace].type == TRC_SMITH && trace[current_trace].channel == channel)
    menu_push_submenu(channel == 0 ? menu_marker_s11smith : menu_marker_s21smith);
  else
    set_trace_type(current_trace, format, channel);
}

static UI_FUNCTION_ADV_CALLBACK(menu_channel_acb)
{
  (void)data;
  if (current_trace == TRACE_INVALID) {if (b) b->p1.text = ""; return;}
  int ch = trace[current_trace].channel;
  if (b){
    b->p1.text = ch == 0 ? "S11 (REFL)" : "S21 (THRU)";
    return;
  }
  set_trace_channel(current_trace, ch^1);
}