95S-1(A) Receiver
![[95S-1]](95s11.jpg)
Introduction
The 95S-1A is a rack-mounted, high-performance receiver
designed for general purpose usage in narrow-band radio
applications. The receiver provides 0.005- to 2000-MHz
frequency coverage and features software-based, state-of-the-art
digital signal processing (DSP). The modern homodyne architecture
and spurious-free MFD synthesizer provide the high performance
necessary for demanding communications and surveillance
applications. A serial control interface allows control via
RS-232/422/485. The receiver draws less than 22 watts from an
internal ac power supply or external 9 to 16 V dc.
Features
0.005- to 2000-MHz continuous coverage in 1-Hz increments.
16-bit DSP.
Full function programmability including: frequency, BFO, bandwidth, sweep, AGC, squelch, volume, demodulation, and calibration.
Selectable digital l/Q output (16 bits).
Standard AM, FM, CW, USB, LSB, and ISB modes.
Seventy-four standard bandwidths selectable from 0.1 to 300 kHz, plus five user-defined downloadable filters.
Spurious-free homodyne and MFD synthesizer circuit architectures.
Dual DSP filtering, demodulation, and processing with programmable demodulation selection and output combining.
Open architecture system: nonproprietary interface specifications are provided, allowing third party customization to any application.
Packaged in a single rack unit chassis (1.72 inches high, 19 inches wide).
RS-232/422/485 serial control.
Applications
The 95S-1A receiver is an excellent choice for any application requiring
computer-controlled tuning of narrow-band radio signals. Several
applications include:
Standard communications modes in the HF, VHF, and UHF bands (ie, AM, FM, CW, SSB) for civil, government, and military networks.
Test equipment.
Spectrum monitoring systems.
The Rockwell Collins 95S-1A general purpose receiver provides high performance at low cost and supports a wide variety of radio receiving applications. The 0.005 to 2000 MHz receiver is designed to satisfy user needs for applications ranging across commercial, government, and military communications, spectrum surveillance and test systems. It is suitable for fixed station, shipboard, or transportable environments.
The receiver serial command protocol is simple and yet minimizes the amount of data that must be transferred between the receiver and the controller. The protocol supports single command operations or can be operated in a multiple command mode that allows a sequence of commands to be executed in succession.
Rockwell Collins has planned the 95S-1A receiver to be an open architecture system, meaning that nonproprietary interface specifications are provided to users, allowing third party customization. Specifically, the memory in the receiver may be altered to download user-written DSP software and alternate control languages. The core Rockwell Collins DSP routines are non-alterable, but may be utilized or supplemented.
![[Block Diagram]](95s1b.jpg)
![[Inside View]](95s1d.jpg)
Frequency range ............. 0.005 to 2000 MHz
Frequency resolution ........ 1 Hz
Tuning time ................. 13 ms (typical), with AGC disabled
Frequency setability ........ +0.1 PPM, using electronic adjustment
of the internal standard
Frequency accuracy .......... +1 PPM, 0 to 50 øC
Synthesizer noise ........... Characterized in the following table:
Frequency Noise Power Noise Power
Separation @fo=100 MHz @fo=1000 MHz
10 Hz -55 dBc/Hz -40 dBc/Hz
100 Hz -90 dBc/Hz -75 dBc/Hz
1 kHz -105 dBc/Hz -94 dBc/Hz
10 kHz -110 dBc/Hz -94 dBc/Hz
100 kHz -135 dBc/Hz -120 dBc/Hz
>1 MHz -145 dBc/Hz -140 dBc/Hz
Noise figure
0 to 30 MHz antenna ....... 14 dB (typical)
20 to 2000 MHz antenna .... 12 dB (typical)
External standard in ........ 1, 5, and 10 MHz
External standard level ..... 0 dBm (typical)
BFO ......................... 1-Hz step, range of +/-4 kHz
Serial control
Interface ................. RS-232/RS-422/RS-485
Data rate ................. 75 to 38,400 bits per second
Format .................... 8 data bits or 7 data bits with 1 parity bit
Internal preselector ........ 20 to 2000 MHz (Dual conversion used for
frequencies below 20 MHz)
Demodulation modes .......... CW, SSB, ISB, AM, FM, I/Q
Carrier operated relay ...... Standard
AM sensitivity .............. 30% amplitude modulation at 400 Hz with
bandwidth of 6.4 kHz for 10 dB (s+n)/n
0.1 to 30 MHz ............. 3 uV
>30 MHz.................... 2 uV
FM sensitivity .............. SINAD of 12 dB with bandwidth of 12.8 kHz
2 to 30 MHz ............... 1.1 uV
>30 MHz.................... 0.5 uV
SSB/ISB/CW sensitivity ...... SINAD of 10 dB with bandwidth of 3.2 (1.6
CW) kHz and the input signal tuned 400 Hz
from the dial frequency
0.005 MHz.................. 13uV (typical)
>0.1 MHz................... 0.4 uV
Second order input intercept
<30 MHz ................... +80 dBm (typical)
>30 MHz.................... +60 dBm (typical)
Third order input intercept
<30 MHz.................... +25 dBm (typical)
30 to 500 MHz ............. +7 dBm (typical)
>500 MHz .................. 0 dBm (typical)
Image rejection ............. >100 dB
IF rejection
<30 MHz ................... >80 dB
>30 MHz ................... >100 dB
Internal spurious ........... Less than equivalent antenna input
of -115 dBm
Conducted LO at antenna ..... <-110 dBm
Manual gain control ......... 1 dB increments
<30 MHz ................... 144 dB range
>30 MHz ................... 126 dB range
AGC range ................... +/-1.5 dB at audio output, with input
signal level range from 10 dB above
noise floor to 0 dBm
AGC programmability ......... AGC attack, hang, and decay time and
threshold values
Standard IF bandwidths ...... 74 programmable between 100Hz and 300kHz
Maximum input level
Operating
<30 MHz ................. +10 dBm
>30 MHz ................. 0 dBm
Nonoperating
<30 MHz ................. +43 dBm
>30 MHz ................. +33 dBm
Signal strength accuracy .... +/-2 dB over 0.1 to 2000 MHz frequency range
Postdetection audio filter .. Software selectable low-pass filters:
4.0 kHz, 25 kHz, 50 kHz, or bypass
Primary antenna input ....... 50 ohms impedance, VSWR <3:1; usable over
input frequency range of 2 to 2000 MHz, with
degraded performance below 30 MHz, compared
to HF antenna input
HF antenna input ............ 50 ohms impedance, VSWR <3:1; usable over
input frequency range of 0.005 to 30 MHz
HF antenna output ........... 50 ohms impedance, internally connected to
the primary antenna input when tune frequency
is below 30 MHz
Phone A&B out ............... 0.5 volt RMS into 100 ohms (max), 1% THD
Line A&B out ................ 0 dBm, 600 ohms (nominal)
Speaker A or B or A+B out ... 1 watt (max), 8 ohms, <10% THD
Input power ................. 9 to 16 V dc, 22 watts 85 to 240 V ac,
47 to 440 Hz
Mechanical
Packaging ................... EIA 1U rackmount, 1.72 in (43.6 mm)
H x 19 in (483 mm) W x 14.75 in (375 mm) D
RF connectors ............... BNC
Audio connector ............. DB1 5F
RS-232 connector ............ DB9F
Weight ...................... Approx 9.0 Lb (4.8 kg)
Operating temperature ....... 0 to 50 øC
Storage temperature ......... -55 to +70 øC
Humidity .................... 95% noncondensing
Shock ....................... Bench handling
Altitude .................... <10,000 ft
Cooling ..................... Convection
Specifications subject to change without notice.
![[Inside View]](95s12.jpg)
The 95S-1(A) receiver is a 0.005 to 2000 MHz high-performance modular receiver employing a direct conversion (homodyne) architecture. The receiver frequency scheme uses only one mix: a single synthesizer local oscillator tuned to the desired signal frequency converts a signal directly to baseband, or the zero-frequency "IF signal." Baseband signal waveforms are filtered and demodulated under the control of digital signal processor (DSP) technologies developed and patented by Rockwell Collins. The advantages realized with a homodyne, or direct conversion receiver (DCR) architecture are simplicity and performance. The DCR provides wide frequency coverage without spurious-generating multiple mixes, and allows receiver selectivity to be obtained using audio low-pass filters rather than the more complex RF/IF filtering required with heterodyne receivers. Additionally, a majority of receiver gain can be applied at baseband rather than in front end RF stages. Because a DCR has no "IF," there is no receiver performance degradation due to "IF" or image rejection. Similarly, there are no "crossover" spurious responses because there is only a single local oscillator.
The 95S-1(A) incorporates a high-dynamic range Rockwell Gallium Arsenide mixer, preceded by internally tracking preselectors over the 20 to 2000 MHz portion of the tuning range. The receiver utilizes a hybrid architecture for frequencies within the 0.005 to 30 MHz tuning range, with parametric upconversion to a 51.2 MHz IF frequency.
An MFD synthesizer with progressive modulo-2 division provides quadrature low-noise, spurious-free injection signals to the HF and VHF/UHF mixers. The quadrature channels are identically low-pass filtered, amplified (with AGC), and digitized by a sigma-delta ADC.
The DSP section utilizes twin 16-bit microprocessors to perform all Finite Impulse Response (FIR) filtering, demodulation, automatic gain control (AGC), and ancillary functions for the receiver. An additional microprocessor provides communications and command execution control. A complement of standard DSP functions is contained within a flash memory integrated circuit, allowing field upgrades and customization. Seventy-four filter bandwidths are standard, and five optional user-defined filter coefficient sets can be transferred to the receiver for specialized applications. Software support and documentation, for developing user-defined FIR filter coefficients for use with the 95S-1(A) receiver, may be purchased from Rockwell Collins or can be developed using standard FIR filter design tools. Two independent demodulators may be operated simultaneously.
Audio output is generated by twin DACs, using any combination of demodulated signals, routed through selectable low-pass filters, and applied to headphone, line, and speaker amplifier circuits.
Digital 16-bit I/Q output is also available with user selectable pickoff points in the DSP signal flow.
All parameters and command settings are preserved in nonvolatile memory. This assures that the receiver operation will be restored whenever power is cycled or a power interruption occurs.
The front panel contains a stereo headphone connector, status indicator lights, and a power switch. Two rear coaxial input connectors allow RF sources (antennas) to be either independently connected between the receiver DCR section (2 to 2000 MHz) and the hybrid converter section (0.005 to 30 MHz), or using the RF output (2 to 30 MHz) connected to the hybrid converter section. The two frequency tuning ranges can be multiplexed internally from a single antenna. The rear 9-pin serial control connector allows for RS-232/RS-422/RS-485 control. Independently adjustable left and right phone channels are available on the headphone connector. The rear panel audio connector provides access to a variety of audio signals including speaker, line, and phone outputs.
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Copyright © Rockwell Collins 1998 & WA3KEY 2000
Photos courtesy of BigBear Lab.
This Home Page was created by wa3key, Wednesday, June 14, 2000
Most recent revision Wednesday, October 29, 2000