Tektronix 1L30, Instruction Manual

Page: 7 / 129

Type H.30
o
&S? a** '^sgi a m ^
Ira*
ii -vki.v M i ’ fe ' va w
f: P \ fi? @*n?a f*> % f? jf *P *e$!a H /^:S>. .P* B t f * '
M m \ i *& r is £('xSk, %sf M u y*8&S id! « v
Change information, if any, affecting this section will be found at the
rear of the manual.
Introduction
A Spectrum Analyzer is an instrument that graphically
presents a plot or relative power distribution as a function
of frequency for a selected portion of the spectrum. The Type
1L30 is designed to provide a spectral display of frequency
distribution of electromagnetic energy within the frequency
range of 925 M H z to 10,500 M Hz. This display provides the
following information: the presence or absence of signals
within a frequency spectrum, their frequencies, frequency
drift, relative amplitude of the signals and the nature of
moduation if any, and many other characteristics.
This section of the manual covers the following: A glossary
of terms; a description and function of the front panel con­
trols and connectors; a first time operational procedure, and
some basic application with signal evaluation.
Installation
The Type 1L30 is designed to operate in any Tektronix
oscilloscope accepting letter- or 1-series plug-in units. It
may also be used with a Tektronix Type 132 or 133 Plug-In
Power Supply, with the output displayed on the CRT of
any oscilloscope that has a 100 or 150 volt sweep output
available. '
If the Type 1L30 Spectrum Analyzer is to be used with the
Tektronix Type 541, 541 A, 543, 543A, 545 or 545A Oscillo­
scope, a modification is required to the plug-in oscilloscope
to correct undesirable display distortion and dispersion non­
linearity. This distortion is caused by a part of the vertical
output signal from the Vertical Signal Out C. F. V1223A
(V1050B, Type 545), feeding into the Spectrum Analyzer on
the + 2 2 5 V supply. The distortion appears as a change of
dispersion linearity with a change of the analyzer G A IN
control setting and is most noticeable in the narrow dis­
persion settings such as 1 kHz/cm. It also appears as a non-
symmetrical response to a C W signal in which the slope of
one side of the signal drops abruptly to the base line. See
Fig. 2-1.
Change the + 2 2 5 volt supply for the Vertical Signal Out
C.F. (V1223A cathode resistor) from the junction of R1008
and R1007 (R1153 and R1152, Type 545) or + 2 2 5 V (DEC)
and connect it to the other side of R1088 (R1153, Type 545)
which is the + 2 2 5 V supply. See Fig. 2-2.
Spectrum Analyzer Terms
The following glossary of spectrum analyzer terms is
presented as an aid to understanding the terms as they are
used in this manual.
©
1
t
11
( f i
/
V
(A) N
ormal respoiwe to a cw signal
J r
(B)
E
feet of dista rtion >n a cw sigr al.
Fig. 2-1. (A) Normal response to a cw signal. (B) Effect of dis­
tortion on a cw signal.
Spectrum Analyzer— A device that displays a graph of
the relative power distribution as a function of frequency,
typically on a cathode-ray tube or chart recorder.
Types: Real-time and non real-time.
A real-time spectrum-analyzer performs a continuous an­
alysis of the incoming signal, with the time sequence of
events preserved between input ond output.
A non-real-time spectrum analyzer performs an analysis of
a repetitive event by a sampling process.
Methods: Swept front end and swept intermediate fre­
quency.
A swept front end spectrum analyzer is a superheterodyne
spectrum analyzer in which the first local oscillator is swept.
A swept IF spectrum analyzer is a superheterodyne spec­
trum analyzer in which a local oscillator other than the first
is swept.
Center frequency (radio frequency or intermediate fre­
quency)— That frequency which corresponds to the center of
the reference coordinate.
Center frequency range (radio frequency)— That range
of frequencies which can be displayed at the center of the
r
rtfr-V'
f:
T
if-
Srj;
2-1