Tektronix H600 RFHawk, Service Manual

Page: 47 / 109

Theory of Operation
Table 2-2: Internal ports and buses (cont.)
Internal port, signal, or
bus
Description
Speaker port
-3 dB bandwidth: 100 Hz to 15 kHz
Speaker: 28 mm diameter, 8 W, 1 W nominal, water resistant
Connector: 2-pin header
Connects to the internal speaker. Outputs platform and
instrument module generated audio. A volume control is
available on the Control Panel (
Start > Settings > Volume &
Sounds ).
Application interface port Logic Levels: 3.3 V signals, 5 V tolerant
Connector: 80-pin blind mate, Molex type
SPI bus signal lines: SPIMISO (master-in-slave-out),
SPIMOSI (master-out-slave-in), SPICLK<6... 1> (SPI clock),
and SPISEL<6... 1> (instrument module select, active low).
The Application Interface port is a full duplex Serial Peripheral
Interface (SPI) bus interface between the platform and the
instrument module.
SPIMISO and SPIMOSI signals are tied together. SPISEL
and SPICLK signals are unique for a module. The platform
signals are always master; all other signals are slave.
The platform addresses the module with a unique SPISEL
signal. The instrument module picks up its SPISEL signal
from the lowest numbered SPISEL pin of the interface
connector on its front case.
Interrupt signals The instrument modules use MODINTR<4... 1> signals for
requesting service from the platform. These signals are
open collector 3.3 V, active low, TTL-level. The instrument
module generates the MODINTR1 signal on the Processor
board. All module interrupt signals are OR-logic wired to form
one interrupt to the CPU. The CPU can then decode which
module asserted the interrupt. Pull-up resistors for these
signals are located on the Processor board.
Audio input signal Signals: AUDIP, AUDIN
Level: 1 Vrms, maximum
Load: 10 kW
Bandwidth: -3 dB, 100 Hz to 15 kHz
A differential analog audio output signals from the instrument
module input to the platform volume control.
Audio output signal
Signals: AUDOP, AUDON
Level: 1 Vrms, maximum
Load: 40 kW per module, 10 kW minimum impedance
Bandwidth: -3 dB, 100 Hz to 15 kHz
A differential analog output signal from the platform built-in
microphone to the input of an instrument modules.
H600 & SA2600 Service Manual 2–5