If your data file looks like this:

Timestamp 12:01:03.348 
0x014D TNDB 
-- 
Result Status: 1 
Source: 2 
Freq: 50 
Slice: 4 
Mode: 3 
Output: 234.209 
Diff: 390.009 
Dev: 89.909 
Timestamp 12:01:03.348 
0x014E TNDB 
-- 
Result Status: 1 
Source: 2 
Freq: 50 
Slice: 4 
Mode: 3 
Output: 234.209 
Diff: 390.009 
Dev: 89.909
[download]

Then this will work:

#!/usr/bin/perl

use warnings;
use strict;
use 5.10.0;

open my $fh, '<', 'data.txt' or die $!;

my $begin = 0;

while ( my $line = <$fh> ){

    chomp $line;
    $begin = 1 if $line =~ /0x014E/;
    next unless $begin;

    say $line and last if $line =~ /^Output:/;
}
[download]

You'll need to paste a couple blocks of your copy/pasted data file into code blocks though. Right below the window you post in describes this clearly

Another way of doing this:

use 5.010;
$/ = "\n--\n";
while ( defined(my $line = <$fh>) ){
    say $1 if $line =~ /\b0x014E\b/ and $line =~ /^(Output: .+)/m;
}
[download]

EDIT: Scratch this answer... I assumed all data on the same line, completely somehow ignoring the title :) Need to see a sample of the actual data in code blocks to better understand.

perl -nE 'say $1 if /\b0x014E\b/ && /.*(Output.*?)\s[^\d]/;' data.txt
[download]