Vectronics VEC-884 - Manual (Page 58)

VEC-884 Owner's Manual
Filter Description 5-6
CW Filter [4]
Use: CW Filter, Narrow FSK.
Passes "razor sharp" to medium frequency width.
The CW filter is an adjustable band-pass filter that can be varied over the
normal frequency range preferred by most CW enthusiasts.
The center frequency (or pitch) is controlled by the Tunable Filters left knob
and has a frequency range of 300 Hz to 1000 Hz. This control functions
similarly to the pass band tuning or the IF shift control of a receiver with this
filter.
The Tunable Filters right knob adjusts the filter bandwidth from 30 Hz to 700
Hz. This knob acts exactly like the selectivity control on a receiver.
Note that as the bandwidth of this filter approaches the on-off rate of the dot
and dashes, some ringing may appear. This is an inherent characteristic of
any filter when the bandwidth approaches the on-off rate. When this filter is
operated using a very narrow bandwidth, some ringing or softening is
inevitable. To minimize ringing use the maximum bandwidth possible.
CW Sidetone Filter
Use: To pass CW sidetone
Passes any signal very near programmed center frequency.
Note:
This is not the preferred method for passing sidetone. This filter will
pass unwanted signals within 30 Hz of the sidetone frequency. See
page 2-5, Passing Sidetone.
The CW sidetone filter is a constant frequency filter used to pass sidetone
through the DSP. It makes the unit operate as two separate parallel filters:
one normal tunable or memory CW filter and the other a constant frequency
sidetone filter.
The CW sidetone filter is set at 50 Hz bandwidth. The filter is jumper
programmable to center frequencies from 300 Hz to 1000 Hz in 50 Hz
increments.