Teledesign Systems Inc TS4000D User Manual

GMSK (BT=0.3)

Gaussian Minimum Shifted Keyed modulation with a BT = 0.3.

This is the less spectrally efficient than 4 Level FSK
modulation and more spectrally efficient than GSMK (BT=0.5)
modulation.

GMSK (BT=0.5)

Gaussian Minimum Shifted Keyed modulation with a BT = 0.5.

This is the least spectrally efficient modulation.  However, it
provides the best BER for a given receive signal level.

Rate

The over the air modulation bit rate.

All TS4000s that communicate together must use the same
setting.  Lower settings result in better signal demodulation
which results in a better (lower) BER (Bit Error Rate) for a
given receive signal level.

The maximum rate that can be set depends on the settings of
occupied bandwidth and modulation type

Active Channel
at Power Down

The channel activated at power up is the channel that was
active when the modem was last powered down.

Fixed Channel

The channel activated at power up is the channel set in the
corresponding control.

This sets the receive signal level at which the receiver is activated.  This is similar
to the squelch control on mobile radios.  Normally this level is set slightly lower
than the level at which the TS4000 can correctly demodulate the incoming data.

When using the TS4000 in a high noise environment, this level can be raised so
that the TS4000 is more selective about the signals that it attempts to
demodulate.  This is important for configurations that do not allow the TS4000 to
transmit while it is receiving.  These include configurations with packet operation
enabled or with the Force Transmit over Receive control disabled.

This control has effect only if packet operation is disabled.

Disabled

The modem will not transmit while receiving.  Transmit data is
buffered and then transmitted when the TS4000 stops
receiving.

Enabled

The modem transmits as soon as data is ready without regard
to the receive state.

When enabled, the timeout timer stops the TS4000 from transmitting after the
specified period of continuous transmission.  This is used to avoid locking up the
radio channel due to a continuous transmission caused by an equipment fault.

This sets the transmit power level. The maximum transmit power that can be set
depends on the specific radio module in the TS4000. Therefore the maximum
value that can be set is listed only when the configuration program is connected
to the TS4000.

This is additional attack time added to the radio transmission process.  This is
used in setups where the TS4000 is used with a power amplifier or repeater
system that creates an extra delay in establishing the radio channel.