12
Subject to change without notice
and time base section are compensated and the trigger slope
becomes visible.
4. YF Board
4.1 The analogue measuring signal is amplifi ed and controls
the Y plates of the cathode ray tube (CRT).
4.2 In digital mode the Y signal and the Y component of the read-
out are input here for Y defl ection. Both signals originate from
data in the Readout FPGA (MC board) which has been converted
by the Readout DAC (MC board) into analogue signals. Whether
the data are displayed as dots or vectors depends on the activa-
tion of the S&H (MC board) circuit in the signal path.
5. MB Board
The main function is to generate sweep (sawtooth) signals in
analog mode for time base A and B in the Sweep A Generator &
Control stage and the Sweep B Generator & Control stage.
The sweep start of both analog time bases is controlled by the
Time Base Control PLD in connection with the Hold Off stage
and the trigger signals coming from the time base A and B
trigger comparators located on YP board.
The sweep defl ection time (coeffi cient) depends on the Shift
/ Store Register data controlling both sweep generators and
the Hold Off stage.
The Delay Comparator controls the time base B delay time,
comparing the A sweep height with a reference voltage.
The Input Control: Sweep A, B, CT-X and XY stage selects between
time base sweep A and B, the X defl ection component of the
component tester (CT) and the signal to be used for X defl ection
in XY mode.
The signals mentioned above are analog mode signals and
output to the X Final Amplifi er, Mag x10, Dig. & Readout Input
& Control stage. Additionally this stage accepts the X defl ec-
tion signal and the X defl ection component of the readout in
analogue and digital mode. Both signals originate from data
in the Readout FPGA (MC board) which has been converted by
the Readout DAC (MC board) into analogue signals. The fol-
lowing S&H (MC board) circuit can be used depending on dots
or vector display. The X fi nal amplifi er controls the X plates of
the cathode ray tube (CRT).
The unblank and intensity information comes from the time
base control. It is converted to analogue via an 8 bit D/A Con-
verter and controls the Blanking Switch & Amplifi er (CR board)
via an Analog Multiplexer and the Blanking Driver stage.
The CT generator generates the X and Y signal components of
the component tester (CT).
The Trace Rotation Buffer Amplifi er provides the trace rotation
coil on the cathode ray tube (CRT) with a current for the com-
pensation of CRT production tolerances as well as the infl uence
of external magnetic fi elds on the sweep.
6. FC Board
This board enables the user to control the instrument via key-
board and rotary pulse encoders. Probes with identifi cations
contacts are recognised and their probe factor is taken into
account. Additionally the user gets information about the ins-
truments state via front panel LEDs and readout information
by aid of the Readout FPGA (MC board).
7. AB Board
The AB board is used for data acquisition. The measuring si-
gnal originating from the YP board is amplifi ed by both Buffer
Amplifi ers and then input at the A/D Converter. The sampling
rate depends on the PLL Frequency Synthesizer from where
the sampling clock signal originates.
The Control Unit FPGA controls the sampling process and
saves the sampling results into a Static RAM. A Time Measu-
ring circuit is additionally used In combination with random
sampling.
After recording, the data are transferred from the Static RAM
to the memories on the MC board.
8. MC Board
The main function of this board is to store and process signal
data captured and recorded by the AB board stages. These data
and the readout data (Readout RAM) are output, converted to
analogue signals and fi nally after controlling the X and Y fi nal
amplifi ers, are displayed by the cathode ray tube (CRT).
The control function for these processes originates from the
PLD stage and control the affected stages via the SPI-Con-
trol-Bus.
Signal and parameter data can also be sent via the Interface
(IFboard) to external devices. It is also possible to receive data
for instrument control, fi rmware update etc.
9. IF Board
This board enables different interface to be input such as
RS-232, USB, Ethernet and GPIB (IEEE-488) for bi-directional
data transfer.
10.PS Board
This board contains a switch mode power supply with different
supply voltages for the instrument. It also contains –2 kV high
voltage generator, the voltage multiplier for 12 kV generation
and the heater voltage. All voltages are required for cathode
ray tube (CRT) operation.
11. CR Board
The CR board contains the Blanking Final Amplifi er, the Blan-
king Switch & Amplifi er, the Focus Control and the Astigmatism
Adjust. stage.
12. USB Host
The USB Host Board contains the control for the USB Memory
Stick Connector.
Short Description of HM1508-2 Boards
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