Rhode & Schwarz Digital VLF-HF Receivers R&S EK895/R&S EK896 Datasheet Manual

							Version
04.00
June
2003
For all shortwave applications from 10 kHz to 30 MHz
◆Compact DSP-based receivers for the 
following applications:
– Radiomonitoring and radio 
detection
– Radiocommunications
– Search operation, DF systems
– Frontend for HF intelligence tasks◆Digital signal processing (DSP) for 
convenient and versatile operation
◆Two models:
– Half-rack receiver R&S EK 895
– Search receiver R&S EK 896
◆Realtime remote control or 
master-slave mode◆Tried and tested system concept
◆Excellent price/performance ratio
◆Extremely reliable operation under 
harsh environmental and EMC 
conditions
Digital VLF-HF Receivers R&S® EK895/R&S® EK 896 
						

							2 Digital VLF-HF Receivers R&S® EK895/R&S® EK 896
Digital VLF-HF Receivers R&S® EK895/R&S® EK 896
VLF-HF Receiver R&S EK 895 
with control panel 
Special features
◆Excellent large-signal behaviour, very 
good intercept points
◆High resolution of tuning frequency 
down to 1 Hz
◆Fast and low-noise synthesizer
◆Demodulators for AM, CW, LSB, USB, 
ISB, FM, FSK, AFSK and FAX included 
in basic configuration
◆13 bandwidths from 150 Hz to 8 kHz 
(quasi-continuous on request) 
◆RF preamplifier, switchable (noise 
figure 8kT
0)
◆Double notch filter
◆Noise blanker
◆DATA LINK reception (option)
◆Passband tuning
◆Syllabic squelch
◆Special RTTY (FSK/AFSK) mark and 
space filters, matched to the selected 
shift◆Digital data output 
◆Maximum input voltage protection up 
to 100 V EMF
◆Control interface fully complying with 
international standards
◆Low power consumption 
						

							Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896 3
Overview
General characteristics of the 
R&S EK 895
With the R&S EK 890 family, Rohde & 
Schwarz is presenting a powerful genera-
tion of VLF-HF receivers which are top-
end products benefiting from many years 
of experience in this field. All members of 
this family are based on the R&S EK 890 
basic model. Due to the advantages of 
digital signal processing, embedded in 
the improved receiver versions R&S 
EK 895/R&S EK 896 a number of addi-
tional features and operational conve-
nience have been added. Straightfor-
ward, menu-guided selection and pro-
gramming of the receiving settings 
ensure excellent processing and handling 
of the received signal content. The com-
pact design is due to the use of large-
scale-integration SMDs. Featuring full 
system compatibility, the receivers pro-
vide the basis for extremely economical 
customer-specific solutions.
With its excellent RF characteristics and 
clearcut, full remote-control capability via 
standardized data interfaces, the R&S 
EK 890 family is suitable for all civil, 
administrative and military shortwave applications. These receivers are an ideal 
choice for receiving systems that have to 
fulfill extremely high reliability require-
ments, in particular under harsh environ-
mental and EMC conditions.
Operation is possible via an ASCII termi-
nal, a computer (PC) or via the front panel. 
Using line drivers, a master receiver can 
control up to 99 remote receivers in mas-
ter-slave operation. On the R&S EK 895/
R&S EK 896, two wired and bus-integrated 
slots for plug-in modules are provided for 
extensions, e.g. BCD interface or input fil-
ters.
Uses
The comprehensive sequence control can 
be used for all demanding shortwave 
reception tasks. Due to flexible program-
ming of the processor, the following oper-
ating modes are possible:
◆Manual operation
◆Remote control or master-slave 
operation
◆Channel scanning, sequential and 
programmable
◆Frequency scan
◆Channel reception
◆Password-protected channel 
reception
Two independent Receivers R&S EK 895 with remote-control panel in a 19“ rackmount adapter
The R&S EK 890 family thus fulfills the 
requirements for versatile use in voice 
receiving and any kind of data communi-
cation system as well as for all radio-
monitoring, radio detection and radio 
intelligence (COMINT) applications. For 
application in DF systems, an R&S EK 895 
is used as the master (controlling synthe-
sizer), its LOs being brought out for exter-
nal amplification, distribution and phase-
locked application to all other receivers.
The built-in memory has capacity for non-
volatile storage of 1000 complete channel 
settings so that channel management 
and control by an external computer are 
not required but are nevertheless addi-
tionally possible. Due to their excellent 
characteristics regarding dynamic range, 
low synthesizer noise and gain control 
range, the receivers are ideal high-perfor-
mance frontends for subsequent signal 
processing. 
						

							4 Digital VLF-HF Receivers R&S® EK895/R&S® EK 896
Search Receiver R&S EK 896
The R&S EK 896 has especially been 
designed for complex tasks of radio 
detection and search reception, its oper-
ating principle and configuration per-
fectly matching the relevant require-
ments. Basically it is fitted with panel 
controls and LCD displays for local and 
remote-control operation. 
High-speed and reliable radiomonitoring 
is supported by temporary storage of a 
complete receiver setup and its transfer 
to or readout from the connected slave. 
The R&S EK 896 is the optimal operator’s 
position in modern radiomonitoring sys-
tems. In the usual master-slave mode, a 
master receiver can control up to 99 slave 
receivers via additional line drivers to 
handle simultaneous radiomonitoring or 
specific radio detection tasks. Due to its 
outstanding characteristics, the R&S 
EK 896 is ideal for use as a standalone 
receiver. All R&S EK 895 options can be 
fitted.
Design
RF unit
The antenna signal is routed via a low-
pass filter, which is provided for rejecting 
image frequencies and suppressing oscil-
lator reradiation, and applied to the input 
mixer where it is converted to the first IF 
of 41.44 MHz by means of an oscillator 
variable in 1 Hz steps. The crystal filter 
that follows determines the maximum 
receiving bandwidth of 10 kHz and rejects 
the second image frequency. A fixed fre-
quency of 40 MHz is used for conversion 
to the second IF of 1.44 MHz.
The high-performance mixer at the 
receiver input ensures excellent large-
signal behaviour. The intercept points are 
typically +70 dBm (IP
2) and +35 dBm 
(IP
3); the crossmodulation transfer is 10% 
for an interfering signal of +21 dBm. In 
most cases, additional filters such as sub-
octave filters are therefore not required.
IF/AF processor (DSP)
The second IF is converted to the third IF 
of 25 kHz using a 5.66 MHz fixed fre-
quency. After digitization of the third IF in 
a 16-bit A/D converter, the processor 
assumes all signal generation and pro-
cessing tasks (DSP) including the follow-
ing:
◆Automatic, remote or manual control
(AGC, DGC, MGC)
◆Measurement of received levels
◆Filtering with 13 fixed or quasi-contin-
uously adjustable bandwidths
◆Demodulation, passband tuning, 
double notch filter
◆Noise blanker, syllabic squelch
◆Generation of BFO frequency as 
analog IF from 0 to 40 kHz, digital IF 
as serial data and I/Q data stream
Synthesizer
The synthesizer supplies all the conver-
sion frequencies required for the RF and 
the IF demodulator units. Due to direct 
digital frequency synthesis, the first con-
version oscillator can be varied in 1 Hz 
steps. The settling time of the oscillator is 
5 ms for any frequency variation. Two 
phase-locked loops (PLLs) produce the 
40 MHz and 5.66 MHz fixed frequencies. 
The operation of the total of four PLLs in 
the synthesizer is continuously moni-
tored.
In the basic version, all the frequencies 
are derived from a temperature-compen-
sated crystal oscillator. Higher accuracy 
requirements can be fulfilled by including 
a heated crystal oscillator (optional 
OCXO) or using an external frequency 
standard (1 MHz, 5 MHz or 10 MHz).
Search Receiver R&S EK 896 with front panel for local/remote control 
						

							Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896 5
Antenna
41.45 MHz to 71.44 MHz
5.66 MHz
Externalfrequencystandard
40 MHzEMCfilter
HeadphonesOption 1 Option 2 
AC supply Output
RS-232-C/
RS-485
interface
Processor Control unitRS-232-C/RS-485Power
supply
TTY
AF 1
AF 2
I/Q RF unit
SynthesizerIF = 41.44 MHz
TCXO
OCXO (option)
A
DDSP
D
A 1
4A D
OptionIF
converter
455 kHz 
IF/AF processor
IF = 25 kHz
IF = 1.44 MHzIF 0 to 40 kHz
or
IF 455 kHz
Digital IF (data,
clock, frame)
Control functions
Processor and software
The 16-bit microprocessor using power-
saving CMOS technology is what makes 
the high-performance, compact, reliable 
and user-friendly concept of the R&S 
EK 895 possible. The microprocessor is 
not only responsible for setting and man-
aging the module functions, it also com-
municates with the outside world via the 
panel controls and the data interface, 
executes the internal programs and 
ensures the high operational reliability 
through various routines:
◆Nonvolatile storage of all settings
◆Continuous testing of CPU, RAM and 
PROM functions
◆Continuous monitoring (CM) of 
synthesizer 
◆BIT (built-in test) for module testing
The simple and logical ASCII command 
syntax for controlling the receiver via the 
serial interface includes control com-
mands for the following:Basic settings
◆Frequency
◆BFO
◆Bandwidth
◆Demodulation modes
◆Gain control mode
◆Digital threshold
◆Passband tuning
Search operations
◆Frequency scanning
◆Channel scanning
◆Hold time
◆Dwell time
◆Stop criterion
Te s t  o p e r a t i o n s
◆Read CM status
◆BIT start
◆BIT readout
System operations
Readout of
◆Software version
◆Options
◆Error messages
◆Signal level
◆Deviation
Channel operations
◆Channel manipulations
◆Store channel
◆Erase channel
◆Select channel
◆Readout channel
Special operations
◆Master-slave operation
◆Complete erasure of channel memory
In addition, the following functions can 
be selected on the front panel:
◆Display of interface configuration
◆Fast channel storage
◆Channel buffer storage
◆Default settings on/off
◆Password for channel service
◆Local/remote mode
◆Knob increments
Block diagram of the Digital VLF-HF Receivers R&S EK 895/R&S EK 896 
						

							6 Digital VLF-HF Receivers R&S® EK895/R&S® EK 896
Rear view of the 
R&S EK 895
Various configurations
Receivers with control panel 
In the standard version, the R&S EK 895 
receiver is available with an operator 
front panel, which can also be retrofitted. 
This front panel also permits manual con-
trol and display of all functions while full 
remote-control capability is maintained. 
This version is particularly suitable for use 
as a master receiver in receiving systems 
or as a standalone unit (standard with 
R&S EK 896).
The operator interface allows for a combi-
nation of hardkey and softkey entries. 
Parameters that are frequently handled, 
i.e. receive frequency, channel, BFO fre-
quency and passband tuning (PBT), can 
be entered directly via a separate keypad. 
All current receiver settings are continu-
ously displayed in large high-contrast 
characters on a backlit LCD. An additional 
bargraph indicator allows display of 
either the receive level (0 to 120 dBµV,  i n  
5 dB steps), the DGC or MGC settings or 
the frequency offset (as a tuning aid and 
deviation indication).
Receivers with remote-control panel
Optionally, the receivers are remote-
controlled by ASCII command sequences 
via a multistandard interface (RS-232-C, 
RS-485, RS-422/423, 2-/4-wire). In the 
simplest case, a terminal can be used as 
the control unit. For more convenience, a 
computer can be used to handle complex 
tasks and to create special user inter-
faces. A demo program for generating a 
virtual front panel is available if desired.
The features newly incorporated into the 
R&S EK 895/R&S EK 896, such as pream-
plifier (PREAMP), noise blanker (NB), 
squelch (SQ), notch filter (NOTCH) and 
passband tuning (PBT), are selected in 
submenus using softkeys. If one of these 
features is active, a bargraph appears on 
the display above the relevant inscription 
(PREAMP, NB, SQ, NOTCH, PBT).
Remote Control Unit R&S GB 899 
(model 03)
This option is an R&S EK 895 reduced to 
control functions plus a Control Panel 
R&S GB 890. It is used for realtime remote 
control of handoff receiving equipment, 
over long distances preferably via addi-
tional modems.
IF bandwidth configuration
The R&S EK 895/R&S EK 896 features 13 
bandwidths from 150 Hz to 8 kHz. Quasi-
continuous tuning in 128 steps is avail-
able as an option.
Input Filter Unit R&S FK 890 H1  
(option)
The input filter module comprises a low-
pass filter, a bandpass filter and eight 
suboctave filters which are automatically 
selected with the receive frequency. 
BCD Interface R&S GC 890 (option)
A plug-in BCD interface is available for 
controlling frequency-dependent add-on 
units with parallel interfaces, e.g. a selec-
tive antenna.
TTY Line Current Source R&S GH 890 
(option)
For the operation of older teletype units 
that require line current (single/double 
current), a TTY line current source requir-
ing no extra slot can be accommodated.IF Converter R&S UX895 (option)
The IF Converter R&S UX895 can be sup-
plied as a submodule for incorporation 
into the  IF/AF processor. Instead of the 
analog IF output signal of 0 to 40 kHz, it 
linearly converts the set receive parame-
ters to the IF of 455 kHz.
Digital Selection R&S FK 896D
(option for R&S EK 896 only)
This option considerably improves the 
input selectivity of the receiver. Two ver-
sions are available for 20 dB or 40 dB 
stopband attenuation. The automatically 
tracking selection circuit includes the fol-
lowing functions: 
◆7-circuit lowpass (0 to 30 MHz)
◆5-circuit lowpass (0 to 1.5 MHz) for 
rejection of strong shortwave interfer-
ing signals
◆Tracking single-circuit filter (1.5 MHz 
to 30 MHz) with a stopband attenua-
tion of >20 dB (40 dB) at 10 % spacing 
from the center frequency
◆Switch on/off by remote control
◆Input voltage protection of ≥200 V EMF
The Digital Selection R&S FK896D is rec-
ommended for use in environments with 
strong RF interference (collocation prob-
lems). It improves input selection by auto-
matically tracking the receive frequency 
and, at the same time, considerably 
increases input-voltage protection 
(overload protection).  
						

							Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896 7
Broadband IF Output R&S GM 893 
(option)
The optional broadband output (plug-in 
module) supplies a 1 MHz output signal at 
the first IF of 41.44 MHz (relative to a 
receive frequency of ±500 kHz). To pre-
vent impairment of the  receiver sensitiv-
ity of the main channel (message chan-
nel), the path to the broadband channel is 
decoupled by approx. 10 dB. For broad-
band spectrum analysis, a spectrum 
display can be connected to this broad-
band output.
Digital data output (option)
For further digital signal processing of the 
received signal, a separate digital IF inter-
face (connector X 69 at rear) is available, delivering the digital DATA, CLOCK 
FRAME outputs (0 to 40 kHz, sampling 
rate 100 ksps).
DATA LINK option
If DATA LINK operation (MIL-STD-188-
203-1A) is required, special receiver ver-
sions are available.
1.44 MHz IF output, unregulated 
(option)
For connecting and operating an external 
IF spectrum display, e.g. the Digital 
Spectrum Display R&S EP 090, an 
unregulated IF output at 1.44 MHz is 
available. This option uses the HF unit 
(model 03) and has to be ordered along 
with the basic receiver.
Setting possibilities of R&S EK 895 down to second menu level
Operating concept
The R&S EK 890 family has a suitable oper-
ating mode for every application (see also 
page 8). The remote-control interface is 
configured to the RS-485 standard and is 
bus-compatible for system operation. 
Users who want to control their radiomon-
itoring system from the receiver front 
panel rather than from a computer can use 
the receivers of the R&S EK 890 family as a 
master receiver or install the Remote 
Control Unit R&S GB 899.
The softkey-menu operator interface pro-
vides the ergonomical advantage of clean 
front panel layout as well as access to a 
large number of setting parameters. When 
you insert extension modules, they are 
automatically detected and incorporated 
in the software BIT and the menu system. 
The clearcut operating concept of the R&S 
EK 890 family has five menu levels which 
allow 50 logically structured operating rou-
tines to be called up by softkeys. In spite of 
the multitude of functions, operation is 
higly convenient, e.g. each type of modula-
tion is assigned a default setting with all 
relevant parameters, which can also be 
individually programmed.
The table to the left shows all possible set-
tings down to the second menu level.
For fast access to the setting parameters, 
the R&S EK 896 has 12 additional hard-
keys, e.g. for standard types of modula-
tion, bandwidth variation, etc. 
Main menu: MOD  GAIN  BW  SCA  MORE
↓Second menu level
MODDemodulation modes
MORE: for further modesAM CW LSB USB MORE
GAINControl modes
Auto, manual, auto+manual, auto+digital
MORE: fast or slow controlAGC MGC A+M A+D MORE
BWBandwidthBW ↓ BW ↑
SCAScan mode
Frequency sweep, channel sweep (any sequence), 
channel sweep (incremental), stop or continue 
sweep, program sweepFRQ CHP CHS S/C PRO
MORE: M/S SYS SPEC CHM MEM
↓
M/SMaster-slave operation
Address slave (indicate slave address, e.g. 62), read 
out or vary slave settingsADR 62 GET PUT
SYSSystem status
Read out firmware version, built-in options, error 
messages; start self-test; MORE: total resetVERS OPT CM BIT MORE
SPECSpecial functions
Rotary knob: step size on/off;
level setting for threshold-controlled external 
switching signal; show serial interface setting; 
switch to remote control; default settings on/offKNOB LEV SER REM DEF
CHMChannel memory parametersChannel memory indication and channel-specific 
parameter variation without interrupting receptionMOD GAIN BW THLD
MEMChannel memory operations
Clear all memory, clear certain memory,
store to certain memory, use next free memoryCLA CLCH STCH STO 
						

							8 Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896
Control concepts of the Digital VLF-HF Receivers R&S EK 895/R&S EK 896
RS-485 bus
Remote control
R&S EK 895 with control 
panel as a standalone unit 
or as a master receiver in 
systems 
Local control
Search Receiver R&S EK 896 
Slave receivers, max. 99 addressable
R&S EK 895 with front panel for remote control
… via PC or ASCII
terminal
Master-slave operation
RS-485 bus
… via the Remote Control
Unit R&S GB 899,
model 03 
						

							Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896 9
Specifications
Frequency range10 kHz to 30 MHz
Resolution1 Hz
Frequency drift
Frequency standard
Oven-controlled frequency standard–10 to +45 ° C  aging/year
5 x 10–7  1 x 10–6
1 x 10–7  1 x 10–7
External frequency standard1/5/10 MHz, 0.2 V to  1 V rms
Antenna inputBNC connector, 50  Ω
VSWR250 kHz< 3 typ. w/o preamp for f >5MHz
otherwise   60 dBm (70 dBm typ.)
> 30 dBm (35 dBm typ.)
Crossmodulation (0.1 MHz to  30 MHz, 
interfering signal 5 V EMF (+21 dBm); 
∆ f ≥ 30 kHz; m = 0.3; f = 1 kHz; signal 
level 10 mV EMF ( −33 dBm))
≤10 % modulation transfer
Blocking (0.1 MHz to 30 MHz; interfer-
ing signal 6.3 V EMF (+23 dBm); 
∆ f≥ 30 kHz; signal level 1 mV EMF
( − 53 dBm); m = 0.3; f = 1 kHz)
≤1 dB signal attenuation
Desensitization (interfering signal 
300 mV EMF;  ∆f ≥ 30 kHz;  signal level 
30 µV EMF; bandwidth 3.1 kHz)
≥ 20 dB SINAD
Inherent spurious signals (f  >100 kHz) 90 dB
IF rejection>90 dB
Weighted S/N ratio for 1 mV EMF>46 dB SINAD
Gain controlautomatic (AGC), manual (MGC) or 
remote (DGC)
AGC error≤3 dB typ. (1  µV to 1 V EMF)
Time response constants
Attack time
Decay time

						

							10 Digital VLF-HF Receivers R&S®  EK 895/R&S®  EK 896
Options
Control Panel R&S GB 890 
(model 03)with controls and indicators for com-
plete receiver setup; connector for 
loudspeaker or headphones 
(max. 1 W into 8Ω )
Remote Control Unit R&S GB 899
(model 03, on request)Control Panel R&S GB 890 plus R&S 
EK 895 reduced to control functions, 
using RS-232-C with a transfer rate of 
50 baud to 19200 baud; modem oper-
ation is recommended for distances 
beyond about 100 m
Input Filter Unit R&S FK 890 H1lowpass filter 0 to 0.5 MHz 
bandpass filter 0.5 MHz to 1.5 MHz 
8 suboctave filters 1.5 MHz to 30 MHz
BCD Interface R&S GC 890frequency information, 22 bit parallel 
(CMOS, 5 V)
TTY Line Current Source R&S GH 890single current: 40 mA/60 V 
double current: ±20 mA/±30 V
IF Converter R&S UX 895
(on request)455 kHz, 0 dBm into 50 Ω,  
BNC female
Digital Selection R&S FK 896D
(R&S EK 896 only)
Frequency range0 to 30 MHz, at f 40 dB: R&S FK 896D, model 
04) at 10 % spacing from center fre-
quency 
(f = 1.5 MHz to 30 MHz)
Gain0 to +2 dB
Tuning time 10 V EMF or >4 A
General data
Broadband IF Output R&S GM 893 
(model 03)
Output frequency41.44 MHz
3 dB bandwidth>1 MHz
Attenuation14 000 h
Power supply100/120/220/240 V −15/+10 %, 
47 Hz to 420 Hz (approx. 25 VA to 
75 VA,  depending on model)
Dimensions (W x H x D), weight 
R&S EK 895
R&S EK 896
211 mm x 132 mm x 460 mm, 
approx. 8 kg
426 mm x 132 mm x 460 mm, 
approx. 11 kg