rx400.pdf

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1、Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 Technical Manual Operation, Maintenance, Installation Instructions and Illustrated Parts Breakdown HF/VHF/UHF DSP RECEIVER RX-400 TEN-TEC, INC. 1185 DOLLY PARTON PARKWAY SEVIERVILLE, TN 37862 Downloaded from www.M manuals search engine Part Number

2、74416 Ten-Tec RX400 Manual Revision 0.5 WARNING HIGH VOLTAGE is used in the operation of this equipment. DEATH ON CONTACT may result if personnel fail to observe safety precautions. Learn the areas containing high voltage within the equipment. Be careful not to contact high voltage connections when

3、installing, operating or maintaining this equipment. Before working inside the equipment, turn power and ground points of high potential OFF before touching them. Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 Table of Contents Item Page 1. Introducti

4、on 4 RF Signal Path 4 HF Signal Path 5 VHF/UHF Operation 5 I.F. Output 5 Control Interface 5 Firmware Updates 5 2. General Information 6 Front Panel Connections 6 Rear Panel Connections 6 Audio Connection 7 3. General Theory of Operation 8 Overview 8 Mechanical Configuration 9 Circuit Descriptions 9

5、 Low Band Preselector 9 Mid Band Preselector 9 First Converter 10 Second Converter 10 Third Converter 10 First Local Oscillator 11 Second Local Oscillator 12 Third Local Oscillator 12 Logic/DSP 13 Power 13 4. Maintenance & Troubleshooting 14 5. Illustrations & Parts Lists 18 Circuit Board Schematic

6、& Parts 21 Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 RX400 DSP RECEIVER This manual provides operation and maintenance instructions for the RX-400 HF/VHF/UHF DSP Receiver. The manual was prepared in accordance with MIL-HDBK- 1221, “Department of

7、Defense Handbook for Evaluation of Commercial Off-The-Shelf (COTS) Manuals. Introduction The RX-400 HF/VHF/UHF receiver couples a rugged wide-band RF front end to a high- performance Digital Signal Processing back end. Multiple detection modes, simplified programming interface and streaming audio ma

8、ke the RX-400 a very flexible platform. Figure 1 Block Diagram RF signal path: The RX-400 contains separate HF and VHF/UHF front ends. The HF section covers the 2-88 MHz range. The range between 88 MHz and 3 GHz is covered by the other. A single antenna connector is used to feed RF signals to the re

9、ceiver. All signals are routed first to the VHF/UHF preselector at which point they are routed to the HF preselector is the tuned frequency is below 88 MHz. In most cases the internal routing of received signals is automatic and there are no user selectable features that affect the front-end operati

10、on. The exception is the HF section, which contains a user-activated RF attenuator. In addition, the IF output bandwidth may be set to 2 MHz or 6 MHz when the tuned frequency is above 20 MHz. Below 20 MHz the IF output bandwidth is fixed at 2 MHz. When the tuned frequency Downloaded from www.M manua

11、ls search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 HF Operation: Signals entering the HF front-end will pass through a user-activated RF attenuator followed by 1 of 8 band-pass filters. Each filter is designed to eliminate potential interference from other undesired signals. The RF

12、 attenuator may be used to reduce interference from undesired signals that may overload the receiver hardware. VHF/UHF operation: For operation above 88 MHz the received signals are routed to the VHF/UHF preselector which covers 88 MHz through 3 GHz (USA versions will not provide access to cellular

13、frequencies except for government authorized users). IF Output: A 21.4 MHz wideband IF output is provided with selectable 6 MHz or 2 MHz bandwidth. Below 20 MHz the bandwidth is fixed at 2 MHz. Control Interface: The RX-400 contains two command and control ports, a standard RS-232 serial interface a

14、nd an Ethernet IP interface. Both interfaces support the same command set with the exception of those features that relate to Streaming Audio. Streaming Audio can be tuned on and off via the RS-232 interface, the Streaming Audio data is delivered only on the Ethernet interface. Firmware Updates: RX-

15、400 Receiver operation, control and demodulation are contained in internal firmware which can be updated in the field. See the RX400 UPDATE INSTRUCTIONS document for details. Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 2. General Information Figure

16、 3 Front Panel Connections Figure 4 - Rear Panel Connections Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 Figure 5 - Audio Connections Pin Description Note 1 Chassis Ground 2 A/C Coupled Mono Audio Unbalanced +10dBm output. 3 Line B- 600 Ohm balance

17、d output. 0 dBm nominal 4 Line B center tap 5 Line B+ 6 Line A- 600 Ohm balanced output. 0 dBm nominal 7 Line A center tap 8 Line A+ 9 Chassis Ground 10 DC Coupled Mono Audio Unbalanced +10dBm output. 11 No Connection 12 User Programmable Output #1 (not available when frequency extender attached) Lo

18、w = 0 volts, High = 3.3v 13 User Programmable Output #2 (not available when frequency extender attached) Low = 0 volts, High = 3.3v 14 User Programmable Output #3 (not available when frequency extender attached) Low = 0 volts, High = 3.3v 15 User Programmable Output #4 (not available when frequency

19、extender attached) Low = 0 volts, High = 3.3v Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 3. General Theory of Operation OVERVIEW The Ten-Tec model RX400 is a narrowband DSP-based receiver with a wide-band IF output available at 21.4MHz. The superh

20、etrodyne architecture is triple-conversion to the IF output for received frequencies of 88 MHz to 3GHz, and double conversion when tuned below 88 MHz. The IF output bandwidth is 6 MHz for tuned frequencies of 20 MHz to 3 GHz, and 2 MHz when tuned below 20 MHz receive frequency. Tuning step size is 1

21、0 kHz (1 kHz optional) at the 21.4 MHz IF output. Conversion gain from antenna to IF output is 3 dB nominal. The GAIN BLOCK diagram outlines the signal path and gain distribution throughout the RX-400 architecture. The 21.4 MHz 3rd IF is bandpass filtered to 300 kHz bandwidth in the 3RD CONVERTER mo

22、dule, AGC leveled, and presented to the DSP board. On the DSP board, a high-speed A/D converter drives an AD6620 Digital Down Converter which applies fine tuning, further bandpass filtering, and decimation to the digitized IF signal to prepare the data for a Digital Signal Processor. Final selectivi

23、ty filtering and mode- specific detection functions are accomplished by the DSP. Audio/Video outputs are available via connectors on either rear or front panel. The outputs are designed for a nominal 600-ohm load. Tuned center frequency, selectivity bandwidth, mode selection, and all other receiver

24、parameter setting is by computer control via rear panel RS232 or Ethernet interface. Only power ON/OFF and Headphone Level controls are user-accessible on the front panel. Figure 6 Block Diagram Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 MECHANICA

25、L CONFIGURATION Six modules located on the bottom chassis deck accomplish the analog frequency conversion functions. These interconnected modules are the FIRST, SECOND, and THIRD CONVERTERS and the FIRST, SECOND, and THIRD LOCAL OSCILLATORS. Signal interconnection between modules is by miniature sem

26、i-rigid coax. Two interconnected PRESELECTOR BOARDS located on the top foldout chassis deck perform frequency band preselection and signal pre-amplification between the antenna input and the FIRST CONVERTER module. The DSP BOARD located on the inner chassis deck performs all digital signal condition

27、ing, detection algorithms, and logic control functions. The DSP BOARD also contains the audio/video output amplifiers and the TCXO master frequency reference. Distribution of control signals and power to the various radio modules and boards is via connectorized ribbon cable between the DSP BOARD and

28、 the target board/module. All DC power is supplied by a shielded universal AC input switching supply located on the inner chassis deck. The DSP BOARD receives the outputs from this main power supply for post-regulation and distribution to the other radio modules. A front-mounted fan supplies forced-

29、air ventilation. Cooling air enters at the front-mounted filter and exits through vent holes around the rear perimeter of the chassis. The front panel board provides both high- speed and low-speed fan connections to allow user-selected air flow and fan noise to suit specific installation environment

30、s. CIRCUIT DESCRIPTIONS The rear panel antenna input is protected by spark gap SV2 and filtered by 3 GHz lowpass FL3 on the MID/HIGH BAND PRESELECTOR board, then routed to the common terminal of 4-position switch U3. Below 88 MHz receive frequency, positions 1 and 2 of U3 and positions RF1 and RF2 o

31、f U1, connect the antenna to the LOW BAND PRESELECTOR board, either directly or through the 20 dB resistive pad R10- 12. Logic lines A1 and B1 determine the U3 switch position. LOW BAND PRESELECTOR Dual PIN diodes D1-8 on the LOW BAND PRESELECTOR select one of eight sub-octave bandpass filters. Each

32、 of the eight filters selects a frequency band approximately 2/3 octave wide to cumulatively cover the Low Band range of 2 to 88 MHz (slightly over 5 1/3 octaves). After bandpass filtering, the selected fractional-octave band is amplified by U2 and passed through 140 MHz band-reject filter L70, L22-

33、25, C19-24. This band-reject filter provides additional attenuation of the Low Band 1st IF frequency. U4 buffers serial data to the PIN diode driver U1. Data from the OUT3 pin of U1 enables power to preamplifier U2 via Q1 and Q2. MID/HIGH BAND PRESELECTOR Position 3 of switch U3 on the MID/HIGH BAND

34、 PRESELECTOR board routes the antenna signal through a bank of seven mid-band filters selected by switches U4 and U5. Logic lines A3, B3, and C3 determine complimentary switch positions of U4 and U5. The first mid band filter is dedicated to the US FM broadcast band of 88-108 MHz. The remaining six

35、filters have approximate 2/3 octave passbands to Downloaded from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 cover 108 to 1650 MHz. The selected filter output is amplified by U2 and lowpass filtered by FIL4 en route to the RF1 terminal of Mid Band / High Band swit

36、ch U6. Position 4 of U3 on the MID/HIGH BAND PRESELECTOR board routes the High Band antenna signals through one of two highpass/lowpass filter cascades selected by switches U7 and U8. Complimentary switch positions of U7/U8 are determined by logic line A4. This arrangement creates two half-octave su

37、bbands of 1650-2200 MHz and 2200-3000 MHz. The selected portion of the High Band is further conditioned by amplifier U9 and highpass filter FIL7 before being presented, along with the Mid Band subband to switch U6. Based on a logical AND combination of lines A1 and B1, switch U6 routes the selected

38、subband through amplifier U10 to the MID/HIGH BAND PRESELECTOR board output. FIRST CONVERTER The FIRST CONVERTER module contains the first mixer and first IF amplifier for all receive frequencies above 88 MHz. The first local oscillator, moving in 2 MHz steps from 2528 to 4090 MHz, is highpass filte

39、red by FIL9, amplified by U7, and applied as high side injection to mixer MX1. On the Mid Band receive frequencies of 88-1650 MHz, MX1 produces a 2440 MHz first IF which is filtered and amplified by the cascade comprising FIL6, FIL1, U2, FIL2, U3, and FIL7, selected by switches U1 and U4. This 2440

40、MHz IF has approximately 80 MHz bandwidth determined by SAW filters FIL1 and FIL2. On the High Band receive frequencies of 1651-3000 MHz, MX1 produces a 1090 MHz first IF filtered and amplified by FIL8, FIL3, U5, FIL4, U6, and FIL5, selected by the complimentary positions of U1 and U4. The 1090 MHz

41、IF has approximately 14 MHz bandwidth determined by dielectric filters FIL3 and FIL4. Connections E4/E5 pass the Low Band 1st LO output of the FIRST LOCAL OSCILLATOR module straight through to the SECOND CONVERTER. SECOND CONVERTER The SECOND CONVERTER module contains the second mixer for all receiv

42、e frequencies above 88 MHz. It also contains the first mixer for receive frequencies below 88 MHz. Each mixer, selected by switch U1, drives a common 140 MHz IF amplifier. Switches U6 and U7 select an IF filter of either 6 MHz bandwidth for receive frequencies above 20 MHz, or 2 MHz bandwidth for us

43、e below 20 MHz. The input Mid Band and High Band first IF frequencies of 2440 or 1090 MHz are mixed with fixed Second LO injection frequencies of 2300 or 950 MHz respectively. Each injection signal is provided by the SECOND LOCAL OSCILLATOR module, filtered by FIL7, amplified by U3, and applied to t

44、he LO port of mixer MX1. On Low Band, the LOW BAND PRESELECTOR board supplies the 2-88 MHz RF signal to the RF port of MX2. The Low Band injection signal is developed in the FIRST LOCAL OSCILLATOR module by dividing a 2272-3648 MHz VCO by 16 to produce 142-228 MHz in 250 kHz steps. This frequency- d

45、ivided first LO is routed through the FIRST CONVERTER module E4/E5 to SECOND CONVERTER E2/FIL6 and U2, then applied to the LO port of MX2. The 140 MHz IF output from switch U7 is lowpass/highpass filtered by FIL5 and C50-52, L10-11, amplified by U8, and routed to the THIRD CONVERTER module via E5. T

46、HIRD CONVERTER In the THIRD CONVERTER module, MX1 is the third mixer for receive frequencies above 88 MHz (Mid/High bands) and the second mixer for receive frequencies below 88 MHz (Low Band). The LO injection signal, developed in the THIRD LOCAL OSCILLATOR module, tunes a 2 MHz range from Downloade

47、d from www.M manuals search engine Part Number 74416 Ten-Tec RX400 Manual Revision 0.5 117.71 to 119.7 MHz in 10 kHz steps (1 kHz optional). Low Band receive frequencies use a 240 kHz segment of this range from 118.48 to 118.72 MHz to fill in the 250 kHz tuning steps produced by the divided-down fir

48、st LO. The third LO injection signal is amplified by U4 and U15 and applied to the LO port of mixer MX1. The 159 MHz trap L11/C70 attenuates a potential image frequency band at the input to U4. The 21.4 MHz IF resulting from this low-side mix provides two outputs from the THIRD CONVERTER module: The

49、 Wideband IF Output at E5 is sampled by directional coupler U1 and lowpass filtered by the L7-L8, C43, C47-C48 combination. This output is either 2 MHz or 6 MHz wide, depending on the receiver tuned frequency, and has 10 kHz (1 kHz optional) tuning resolution. The Narrowband Output is filtered to 300 kHz bandwidth, amplified and AGC leveled, th