Start with subplot and mung on it a little...
hSp(1)=subplot(3,1,1); % two subplots in space for three
hSp(2)=subplot(3,1,2);
set(hSp,{'XTick'},{[]});
set(hSp,{'YLim'},{[0.5 1]},{'YTick'},{[0.5:0.1:1]}); % set y limits, clear x ticks
yields
as starting point. You could close up the spacing between the two by retrieving the 'Position' vector for the second and adding a little to the bottom position if desired.
pos=hSp(2).Position; % get position of lower axes
pos(2)=pos(2)+0.05; % add a little to the bottom position
hSp(2).Position=pos; % reset there
Salt to suit...
ADDENDUM
z=exprnd(1,100,1); % first dummy data to plot
RP(:,1)=-z/2/ceil(max(z))+1; % scale roughly same y-axis
z=exprnd(0.1,100,1); % second different parameters
RP(:,2)=-z*0.25+1;
s=linspace(39,45,100); % seconds time array to match
hold(hSp(1),'on') % keep plot() from resetting everything
plot(hSp(1),s,RP,'+') % and plot onto the first axes
ylabel(hSp(1),'Rp') % y axis label
box on % outline
The pattern to follow for the second axes should be clear; use your data variables obviously. The above produced
ADDENDUM 2
And to add the annotation is also fairly straightforward--
hSp(3)=subplot(3,1,3); % make another axes to write into
pos=hSp(3).Position; % retrieve its default position
pos(4)=pos(4)+0.1; % move it up, too
hSp(3).Position=pos; %
xlim(hSp,[39 45]) % apply same x axis range
set(hSp,{'XTick'},{[]}); % various clean up to leave blank
hSp(3).YTick=[]; % canvas to write onto
hSp(3).XColor='none'; hSp(3).YColor='none';
hF=gcf; hF.Color='w';
x=[39:45]; % the values to write at
hTx=text(x,ones(size(x)),num2str(repmat(5.7,7,1)),'Horizontal','center');
hTx=[hTx,text(x,ones(size(x))-0.1,num2str(repmat(5.9,7,1)),'Horizontal','center')];
hTx=[hTx,text(x,ones(size(x))-0.2,num2str(repmat(6.4,7,1)),'Horizontal','center')];
hTx=[hTx,text(x,ones(size(x))-0.3,num2str(x.'),'Horizontal','center')];
r=pos(1)+pos(3); % right side location absolute
pos(3)=0.75*pos(3); % shrink horizontal width
pos(1)=r-pos(3); % find left start point
hSp(3).Position=pos; % and resize to match
l=pos(1);w=pos(3); % save the left and width positions
for i=1:2 % make the other two match up...
pos=hSp(i).Position;
pos(1)=l;pos(3)=w;
hSp(i).Position=pos;
end
ends up with
