9
two preset frequencies. Note that depressing a push-button always selects the first of the two
parameters. Factory settings for center frequencies are 600 Hz. and 800 Hz. Refer to the
Back Panel Jumper Function Table on page 12 for details on the Jumper 4,5,and 6 settings.
Two parameter select push buttons, marked "100/500" and "200/500", select the bandwidth of
the CW filter. These buttons select a bandwidth of 500, 200 or 100 Hz. When both bandwidth
select buttons are out, the bandwidth is 500 Hz. When the "200/500" button is pushed in and the
other bandwidth select button is out, the bandwidth of the CW filter is 200 Hz. If the "100/500"
bandwidth select button is pushed in, it has precedence and the CW filter bandwidth is 100 Hz,
independent of the state of the other button. No matter what the state of the three CW filter
switch settings on the DSP-9+ front panel, one of the six preset CW filters is always active in the
CW mode.
The CW mode can also operate with random noise reduction. To enable the random noise
reduction feature for CW operation, simply press in the button marked "NRr".
CW AGC
The AGC (automatic gain control) can add up to 18 dB extra gain for weak signals, and can
control the variation in levels of stronger signals. Depress the “AGC” push-button to turn on
the AGC. Use the AGC whenever it enhances the readability of a signal. Sometimes, the AGC
appears to increase the noise level because of the additional gain of the AGC. This is normal
when signals are weak, and may enhance readability in spite of the higher audible noise.
CW Bypass Mode
Depressing the Bypass push-button places the DSP-9+ into a bypass mode. In this mode, a relay
connects the audio input jack of the DSP-9+ directly to the speaker and headphone output jacks.
The relay also connects the audio input jack of the DSP-9+ to the line output jack via a 6 dB
attenuator. The Bypass mode has precedence over the CW modes. When the DSP-9+ is in
bypass, the settings of the gain control and the parameter select push buttons do not affect the
signal. Turning off or removing power from the DSP-9+ automatically de-energizes the relay
and forces the DSP-9+ into the bypass mode.
Data Mode
In the Data mode, the DSP-9+ filters the audio input using one of sixteen data filters for RTTY,
AMTOR, PACTOR, G-TOR or HF Packet. There are four choices of mark-space frequency
pairs. Each mark-space frequency pair has four filters, one each for RTTY, AMTOR, PACTOR
and HF PACKET. Two Back panel jumpers preset one mark-space filter frequency pair from
the four available frequency pairs. After presetting the mark-space frequency pair (or using the
factory setting), select the desired data filter by pressing the RTTY, AMTOR, PACTOR, or HF
Packet push-button (use HF Packet filter for G-TOR). If more than one push-button is depressed
at the same time, the narrowest data filter has precedence (RTTY = 260 Hz, AMTOR = 340 Hz,
PACTOR =440 Hz, HF Packet = 540 Hz). If no data filter push-buttons are depressed, a
wideband filter (100-3700 Hz) is active with a delay equal to the data filters, and AGC is active
(if selected).
The mark-space frequencies of the modem, receiver and DSP-9+ must match.
