Types Of Modulation; Amplitude Modulation (Am) - Hameg Instruments Hm8135 Handbuch

Example 1:
CH1— > modulation: fi rst pulse width 150 s
second pulse width 1.1 ms
period 2.5 ms (Fmod: 400 Hz)
CH2— > moduled signal (deviation: 2 kHz)
Example 2:
In this example, the external modulation signal is a "trinary"
code composed of 9 bits. One bit is composed of 2 narrow and
/ or wide pulses, depending on the combination expected:
– A bit composed of 1 wide and 1 narrow pulses is called
OPEN.
– A bit composed of 2 narrow pulses is called LOW.
– A bit composed of 2 wide pulses is called HIGH.
For detecting the fi rst bit, a synchronisation bit (long low level)
is present. The modulation frequency is 20 Hz.
CH1— > modulation: narrow pulse of 200 μs
wide pulse of 1.8 ms
synchronisation bit of 14 ms
CH2— > zoom of CH1
T y p e s o f M o d u l a t i o n
CH1— > demodulated signal: DC coupled
CH2— > demodulated signal: AC coupled
The return to the modulation menu is possible by pressing the
PREV. key and the return to the main display by pressing
the ESC key .
The external modulation input is on the front panel (MOD. INPUT
). The signal can be of any shape, however the AM-depth and
FM/PM deviation programmed is calibrated only for a 2 V
signal at the input.

Types of Modulation

Amplitude modulation (AM)

After selecting D% (AM MEMU) using the context sensitive keys
, the display shows:
A new value of the modulation depth can be entered from the
data keypad or modifi ed by the digital rotary
the four context sensitive keys
The modulation depth may be changed from 0 to 100% with a
resolution of 0.1%.
The return to the previous menu is possible by pressing the
PREV. key and the return to the main display by pressing
the ESC key .
Example 3: For AM sine (depth: 50%), the display shows:
or by one of
.
Subject to change without notice
RMS
31