Table of Contents
Advertisement
Available languages
Available languages
a) The largest input signal does not exceed the optimum input
level of the analyzer (typically –30dBm with 0dB input at-
tenuation).
b) The peak of the largest input signal rests at the top of the
CRT display (reference level).
Frequency Response
The frequency response of an analyzer is the amplitude linearity
of the analyzer over its frequency range. If a spectrum analyzer
is to display equal amplitudes for input signals of equal amplitu-
de, independent of frequency, then the conversion (power) loss
of the input mixer must not depend on frequency. If the voltage
from the LO is too large compared to the input signal voltage
then the conversion loss of the input mixer is frequency depen-
dent and the frequency response of the system is non linear.
For accurate amplitude measurements, a spectrum analyzer's
response should be as fl at as possible over its frequency ran-
ge. Flatness is usually the limiting factor in amplitude accura-
cy since it is extremely diffi cult to calibrate out. And, since the
primary function of the spectrum analyzer is to compare signal
levels at different frequencies, a lack of fl atness can seriously
limit its usefulness.
Tracking Generator
A tracking generator is a sine wave generator that is frequency
controlled by a spectrum analyzer in such a way that the gene-
rator frequency and the spectrum analyzer receiving frequency
are always equal. In ZERO SPAN mode the tracking generator
provides a discrete sine wave frequency equal to the center fre-
quency. In SPAN mode the tracking generator frequency preci-
sely tracks the spectrum analyzer.
The tracking generator can be used for frequency response (am-
plitude vs. frequency) measurement on amplifi ers, attenuators
and fi lters. The generator output voltage should be applied to the
input of the device under test, and the device output connected to
the analyzer input. In this confi guration, the spectrum analyzer/
tracking generator becomes a self contained, complete (source,
detector, and display) swept frequency measurement system.
An internal leveling loop in the tracking generator ensures a
leveled output over the entire frequency range.
R S - 2 3 2 I n t e r f a c e – R e m o t e C o n t r o l
RS-232 Interface – Remote Control
Attention:
All terminals of the RS-232 interface are galvanically con-
nected with the instrument and subsequently with protective
(safety) earth potential.
Measurement on a high level reference potential is not permitted
and endangers operator, instrument, interface and peripheral
devices. In case of disregard of the safety warnings contained
in this manual, HAMEG refuses any liability regarding personal
injury and/or damage to equipment.
Operation
The spectrum analyzer is supplied with a serial interface for
control purposes. The interface connector (9 pole D SUB female)
is located on the rear of the instrument. Via this bi-directional
port, the instrument can be controlled and the parameter set-
tings and signal data can be received from a PC.
RS-232 Cable
The maximum connecting cable length must be less then
3 meters and must contain screened lines connected 1 : 1. The
instrument RS-232 connection (9 pole D SUB female) is deter-
mined as follows:
Pin
2
Tx data (data from instrument to external device)
3
Rx data (data from external device to instrument)
5
Ground (reference potential - connected via the
instrument power cord with protective earth)
9
+5V supply for external device (max. 400mA).
The maximum voltage swing at pin 2 and 3 is ± 12 Volt.
RS-232 protocol N-8-1 (no parity bit, 8 data bits, 1 stop bit)
Baud Rate Setting
After switching the instrument on, the default setting of the RS-
232 port is always 4800 baud. It can be changed thereafter to
9600, 38400 or 115200 baud by a command listed below.
Data Communication
After switching on the instrument it always automatically trans-
mits HM5014-2 with 4800 baud. A data carrier with a program
executable under Windows 95, 98, Me, NT 4.0 (with actual ser-
vice pack), 2000 and XP is part of the delivery. Updates can be
found on the Internet under www.hameg.de.
Commands from PC to HM5014-2
General description: Each query/command must be introduced
with „#" [23 hex = 35 dec] followed by respective characters, i.e.
TG for Tracking Generator, and further followed by parameter,
which are explained in detail below. Each command is executed
by pushing the „Enter" key (hex: 0x0d). No differentiation is ma-
de between capital and lowercase letters (i.e. TG = tg). Units of
measurement are always defi nite (i.e. span value given in MHz)
and are therefore not indicated.
Setting Commands:
(E)
= stands for keyboard Enter
(CR)
= Carriage Return pushbutton
#kl0(E)
= Key-Lock off
#kl1(E)
= Key-Lock on (RM (Remote) -LED is lit)
35
Subject to change without notice
Advertisement
Chapters
Table of Contents
