VI-2
The voltage required by the directional coupler is generated with a standard linear voltage regulator,
U103 if it is a voltage other than +5Vdc. C107 and C108 helps clean up any ripple or noise that
might be on the output voltage. In the standard configuration, where the directional coupler requires
+5Vdc, the +5Vdc is simply taken from the U101 filtered power supply output.
Interface Components
The interface section of the Series II – rev I PCB includes the front panel switch interfacing in
addition to the buzzer and carrier disable output circuits.
The (4) membrane switches found on the front panels of each enclosure are tied to the
microcontroller through an isolation stage to avoid any static discharge or noise on the switch
wiring from reaching the microcontroller. Optoisolators U105 and U106, in addition to
components R104…R115 create the necessary isolation to the sensitive microcontroller. By
depressing any membrane switch, a ground (0V) is applied to the input of the optoisolators. The
optoisolators will, in turn, output a ground (0V) to the microcontroller when any switch is
depressed.
The membrane switches found on the front panels of the enclosures operate in the following
manner with a depress:
POWER –
When unit is plugged in, AC is supplied to the switching power supply input, but
the amplifiers are still turned off. In order to turn the amplifiers on, assuming the rocker switch
is turned on, wait ten seconds after plugging the PA in and push in the “POWER” tactile
button. The LCD will read “Soft Start Warm Up, Please Wait”. After ten seconds the bias
voltages will be turned on and you may then plug in the RF drive. Depress for (1) second to
turn on and (3) seconds to turn system off. In the case of multiple enclosures, all POWER
switches are tied together in each enclosure, so only one switch needs to be depressed.
NAVIGATE –
Turns on backlight to LCD and displays forward and reflected RF power and DC
supply voltage parameters. When power amplifier is first turned on, the LCD comes on
automatically and this information is displayed. Information is displayed for several minutes
before the backlight turns off and the display is cleared. This is set up so as not to burn any
pixels into the LCD from extended on time. In the case of multiple enclosures, the NAVIGATE
switches are individual to each enclosure.
SELECT –
Turns on backlight to LCD and displays forward and reflected RF power and DC
supply voltage parameters. When power amplifier is first turned on, the LCD comes on
automatically and this information is displayed. Information is displayed for several minutes
before the backlight turns off and the display is cleared. This is set up so as not to burn any
pixels into the LCD from extended on time. In the case of multiple enclosures, the SELECT
switches are individual to each enclosure.
