Belar FMHD-1, Руководство оператора

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FMHD-1 Operator’s Manual
BELAR ELECTRONICS LABORATORY, INC. Page 27
Four internally generated signals may also be directed to any of the fourteen FMHD-1 rear-panel outputs
for external testing. They consist of three 1-kHz single-frequency tones at the relative levels of 0dB,
–3dB, and –6dB, and a mute, or null signal. These are designated as “
TST
0”, “
TST
–3”, “
TST –6
”,
and “ Mute ”. The Mute signal may be activated to check the noise floor of connections to the FMHD-1 ,
as well as to provide a quiet source for external testing. These four test signals also are available in the
two channels of the front-panel headphone jack.
Analog output channels 1 through 8 employ active-balanced output circuitry designed to drive 600-
Ω
differential loads. If used to drive unbalanced loads, the alternate output (either pin 2 or pin 3 of the XLR
chassis plug) should be connected to pin 1 of the same connector with a short lead. Note that while the
two outputs of the active-balanced pair may be used to drive separate unbalanced loads, imperfect loading
of the line balancing mechanism of the circuit results in interaction between the two outputs.
Analog outputs 1 through 8 employ a DC servo circuit greatly suppresses any DC present in the output
signals while minimizing any waveform tilt that might be introduced by conventional high-pass filtering.
The three AES/EBU coaxial BNC output jacks source six output channels in the pairs “
CH 1–2
”, “
CH
3–4
”, and “
CH 5–6
”. The lower data word carries the lower (odd-numbered) output channel signal; the
upper data word carries the higher (even-numbered) output channel signal. The signal data is 24-bit.
The settings for the FMHD-1 front-panel headphone output are at the bottom of the Outputs Popup
Menu. As for the analog and digital programs above, one of the fifty-two audio signals and four test
signals may be chosen for either the Left or Right headphone channel outputs. The sources are chosen by
the encoder knob with the cursor placed adjacent to either the “
L:
” or “
R:
” at the bottom of the screen.
Placing the cursor at, and then highlighting in green, the number displayed to the right of “
Vol:
” permits
adjustment of the headphone volume. Subsequent rotation of the encoder knob adjusts the L- and
R-channel headphone volumes, as a pair, from 1.0% to 100.0% in 1% increments.
6.3.3 Network Status Popup Menu
This sub-menu is accessed through the
Network
selection in the Settings Popup Menu.
This menu provides information about the addressing of the FMHD-1 for Internet communications and is
read-only. Pressing the encoder knob with “Refresh” highlighted green updates the status indications.
6.3.4 Network Configuration Popup Menu
This sub-menu is accessed through the
Network
selection in the Settings Popup Menu.
The FMHD-1 offers either fully automatic Internet Protocol device addressing via DHCP, or fully
manual address entry.
When “
DHCP
” in the configuration menu is set to “
ON
”, the IP Address and the Subnet and Gateway
settings are handled automatically. In this case, they all read “<DHCP>”.
With
DHCP
“
OFF
”, all network connection settings must be entered manually. At each grouping of
numbers in the identifiers for the IP Address and the Subnet and Gateway, the encoder is used to select a
number in the range of “0” to “255”. When the process is complete, move the cursor to “
Apply
” and
press the encoder knob. The Status readout at the bottom of the popup menu will indicate the initiation
and processing of the update (“
Configuring
”, “
Rebooting
”), success or failure and, finally, the
connection activity.