Frequenca Response; Tracking Generator; Rs232 Interface - Remote Control; Safety - Hameg Instruments Hm5012-2 Handbuch

Introduction to Spectrum Analysis
This is the level we must be able to detect, and the bandwidth
required for this sensitivity must not be too narrow or it will
be useless. Last, the display range must be adequate.
Notice that reducing the level at the input mixer can extend
the spurious free measurement range. The only limitation
then, is sensitivity. To ensure a maximum dynamic range on
the CRT display, check to see that the following requirements
are satisfied.
1.The largest input signal does not exceed the optimum input
level of the analyzer (typically –30dBm with 0dB input
attenuation).
2.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
amplitude, 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 dependent and the frequency response of the
system is non linear. For accurate amplitude measurements, a
spectrum analyzer's response should be as flat as possible over
its frequency range. Flatness is usually the limiting factor in
amplitude accuracy since it is extremely difficult to calibrate
out. And, since the primary function of the spectrum analyzer is
to compare signal levels at different frequencies, a lack of flatness
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
generator 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 frequency. In SPAN mode the tracking generator
frequency precisely tracks the spectrum analyzer.
The tracking generator can be used for frequency response
(amplitude vs. frequency) measurement on amplifiers,
attenuators and filters. 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 configuration,
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.
42
(HM5014-2 only)
RS-232 Interface – Remote Control
RS-232 Interface – Remote Control

Safety

Caution:
All terminals of the RS-232 interface are galvanically
connected 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 HAMEG HAMEG HAMEG refuses any liability regarding personal injury HAMEG
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
settings 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
determined 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
transmits HM5012-2 or HM5014-2 with 4800 baud.
A data carrier with a program executable under Windows 95,
98, Me, NT 4.0 (with actual service pack), 2000 and XP is part
of the delivery. Updates can be found on the Internet under
www.hameg.de.
Subject to change without notice