Advanced Features

EDSP

EDSP FUNCTIONS

The EDSP circuitry in the MARK-VFT-1000MPal- lows digital enhancement of both transmitted and re- ceived audio. A basic primer on DSP was given to in- form you more about this capability than just the panel label and button location. Now you can customize its filtering capabilities and use it to reduce QRM and tai- lor audio response for each operating mode.

EDSP Modulation

TX Audio Enhancement (Menu 4-4)

Four microphone audio responses can be chosen using menu selection 4-4. Since voice audio character- istics vary between people, these settings enable tai- loring your transmitted audio for best clarity.

TX IF Filter Selection (Menu 5-9)

Normally, 2.4 kHz filters are selected for both the 455 kHz and 8.2 MHz Tx IF. However, with EDSP op- eration, you can keep the 2.4 kHz filter, or select the

6.0kHz filter for maximum bandwidth and better fre- quency response on your transmitted audio. The re- sulting effect of this filter selection is directly related to menu selection 7-7(below). The desired filter is chosen with menu selection 5-9, and is only active when EDSP is turned on. Note that your signal’s actual bandwidth on SSB will not exceed that set by the IF analog filter, with a (-6 dB) bandwidth of approximately 2.4 kHz be- ing typical.

EDSP Modulation/Demodulation (Menu 7-7)

TX EDSP Modulation - Early-stage transmitted SSB audio may be applied directly to the EDSP cir- cuitry for processing, bypassing the analog modulator. EDSP filter parameters can be matched to voice char- acteristics for optimum audio tailoring.

RX EDSP Demodulation - For SSB, CW and AM, receiver 3rd IF output is applied directly to EDSP cir- cuitry for demodulation and processing, bypassing the analog product detector. Reduced noise is a primary benefit of the EDSP Demodulator, which may be used alone or in conjunction with EDSP filtering.

Menu selection 7-7configures the settings for both the RX and TX EDSP modulation circuits (see table at the right). Note also that if the EDSP is turned off via menu selection 0-9, these circuits will revert to their ana- log counterparts.

EDSP RX AUDIO ENHANCEMENT

EDSP Contours

QRM reduction is accomplished by uti- lization of the various DSP filter networks. The front CONTOUR buttons select Low-

( button,) Mid- ( button,) and High-

cut ( button) filters, along with a band pass filter selection (see below).

The low-, mid-, and high-cut filters are pre-set for different audio emphasis, using mathematical algorithms developed after thousands of hours of on-the-air testing. The bandpass filter, activated when the [IDBT] button on the Shuttle Jog is pressed, is automatically pro- grammed to match the analog IF passband established by the setting of the WIDTH and SHIFT controls. No manual sdjustment is required.

This CONTOUR LED indicates the current status of the EDSP Contour feature:

Glowing Green: Low-cut filter selected,

Glowing Orange: Mid-cut filter selected,

Glowing Red: High-cut filter selected,

Off: EDSP Contour Off.

In actual operation, it may be very difficult to “pre- dict” which Contour response will best enhance the sig- nal-to-noise recovery. So under difficult conditions, you should change selections often; don’t be surprised if one selection suddenly causes the incoming signal to “jump” out of the background noise.

EDSP CONTOUR SELECTIONS

CONTOUR

Filter Type

Application

Selection

 

 

 

LCF (Low - Cut)

high-freq. empasis

 

 

 

 

MCF (Mid - Cut)

high & low freq.

 

empasis

 

 

 

 

 

 

HCF (High - Cut)

low-freq. empasis

 

 

 

EDSP MODULATION & DEMODULATION

MENU SELECTION “7-7”

Mode

Settings

SSB (RX)

OFF

100 ~ 3100 Hz

 

300 ~ 2800 Hz

 

OFF

SSB (TX)

100 ~ 3100 Hz

150 ~ 3100 Hz

 

200 ~ 3100 Hz

 

300 ~ 3100 Hz

CW (RX)

OFF

ON (100 ~ 3100 Hz)

 

AM (RX)

OFF

ON (70 ~ 3800 Hz)

 

MARK-V FT-1000MP Operating Manual

page 73

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Image 75
Vertex Standard FT-1000MP manual Edsp Modulation, Edsp Contours, Edsp Functions, Edsp RX Audio Enhancement