Yaesu Mark-V FT-1000MP Operating Manual: Advanced Features

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Advanced Features

Enhanced Digital Signal Processing uses A/D (Ana-
log to Digital) and D/A (Digital to Analog) conversion
techniques under microprocessor control to achieve
significant enhancement of signals at the audio and
low-frequency IF levels. The major capabilities offered
by EDSP lie in the area of heterodyne/random noise
reduction and audio bandpass filtering. Digital filters
have many advantages over their analog counterparts
in that they can meet tighter specifications on param-
eters such as voltage and temperature drift and noise
problems. And the hybrid filter architecture of the
MARK-V FT-1000MP, utilizing extensive analog IF fil-
tering to protect the DSP circuitry which follows, guar-
antees superior strong-signal performance under
crowded band conditions.
The MARK-V FT-1000MP uses a 16-bit NEC
µPD77016 CMOS digital signal processor chip featur-
ing a 30-nS Instructions Cycle, 33 MHz Clock fre-
quency, a 16 x 16-bit and 40-bit multiply accumulator,
40-bit Barrel Shifter, and 64 K Bytes Program ROM.
DSP enhancement is basically a four-step process.
Audio (or EDSP IF) input is sampled several thousands
of times per second, then the frequency and ampli-
tude of the audio are converted into a digital represen-
tation of the analog waveform that resembles ascend-
ing and descending "staircases" by the A/D (analog-
to-digital) converter. This is later changed into digital
serial bitstream as raw data for analysis and process-
page 72
Information is extracted from digital data, and the
EDSP chip performs complex mathematical calcula-
tions according to pre-programmed routines known as
algorithms. Algorithms are processed then compared
against a set of parameters (or threshold if you will)
based on a phenomenon known as "correlation." The
degree of correlation depends on the incoming signal's
characteristics: random noise has relatively little cor-
relation, speech contains moderate correlation, with
heterodynes (and QRM) being highly correlated. The
EDSP microprocessor is programmed with various
parameters corresponding to different known audio
EDSP allows the frequency spectrum of a received
signal to be modified according to a specific set of pa-
rameters for the desired effect (QRM reduction, audio
tailoring, etc.). Certain types of audio interference leave
a distinctive signature or "footprint," which can be rec-
ognized, and "processed out" of the digitally-recon-
structed audio from the EDSP chip. Also, digital filters
are constructed which emulate traditional low-pass,
high-pass, band-pass, and band-stop filters, except with
steep skirt shaping and performance possible with digi-
tal technology. EDSP also allows direct "digital" de-
modulation of audio for receive, as well as direct modu-
lation of audio for transmit.
MARK-V FT-1000MP Operating Manual


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