遥测发射机中的微波锁相调频技术研究

本文介绍了再入遥测系统中发射机的微波锁相调频技术,分析了几种微波锁相调频方案构成及其电路的性能和应用。研究结果表明,两点注入式微波锁相调频适用于高码速率、宽频带与调制响应要求比较高的遥测系统。     

再入遥测中的微波锁相调频技术

介绍了一点注入式和两点注入式微波锁相调频技术，及其在再入遥测中的应用，分析了锁相调频中的噪声性能和环路中分频器对调频的影响。     

一种高码速率微波锁相调频源

适应２Ｍｂ／ｓ ＰＣＭ信号的微波锁相调频源将是二十一世纪遥测系统发射设备中的重要部件。文中介绍了该调频源研制中使用的关键技术－－次两点注入式调频技术，以及相关电路设计和实验结果。理论分析和实践表明，准两点注入式锁相调频源具有平坦的宽带调制特性，能满足高码速率遥测发射设备的实际要求。     

S波段连续波调频发射机

Ｓ波段连续波调频发射机是为某飞行试验再入遥测研制的空载发射设备。它采用了分频锁相调频振荡和微波功率放大组合结构方案,其电路结构简单,调试较容易,杂波抑制比较高,工作性能稳定可靠。本文介绍了该发射机的工作原理,主要技术问题和解决办法,以及研制结果。     

卫星频段新型锁相环路宽带调频技术研究

宽带调频技术是卫星通信技术中的关键技术之一。介绍了一种准两点注入式锁相宽带调频技术,理论分析表明在准两点注入式锁相调频中,只要合理地设计积分器,选择合适的积分常数,其调频特性将为一平坦的直线,即可得到与环路响应无关的宽带调制特性。这一技术特性正好满足高速率信号的调频技术。这种方式很好地解决了调频时环路带宽选择受到调制频率限制的问题,从而可以获得平坦的宽带调频响应,给出相关电路的设计和实验结果。     

S波段数字分频锁相调频振荡源

介绍了一种工作在Ｓ波段，全数字分频锁相调频振荡源的电路构成方案、工作原理、设计方法和实验结果。该调频振荡源电路结构简单，调试容易，工作稳定性好，在再入遥测发射设备中有较大的实用价值。     

小型化S—波段弹上遥测发射机

本文采用锁相技术研制了小型化弹，上遥测发射机，采用一些新颖器件，设计了高速宽带锁相环，实现了弹上发射机的高码速率、大频偏和高线性度，研制的发射机可适用于各种弹上遥测设备。     

小型化S－波段弹上遥测发射机

本文采用锁相技术研制了小型化弹上遥测发射机，采用一些新颖器件，设计了高速宽带锁相环，实现了弹上发射机的高码速率、大频偏和高线性度．研制的发射机可适用于各种弹上遥测设备．     

小型S波段锁相遥测发射机

文中首先介绍了ADI公司的频率综合器ADF4360—1的主要特性,然后结合锁相调频的基本原理,给出了基于ADF4360—1单芯片的S波段锁相遥测发射机的设计方案。着重分析了关键参数的设计方法及其实现方法,同时给出了实例,且实例已得到了实际应用。     

测控系统中收发间的频率干扰及锁相调频器的分析与设计

若在测控系统中,发射机方案考虑不周,将导致发射机对接收机的频率干扰,本文简要分析了干扰的影响,为减少发射机的寄生信号输出,提出在发射机末前级采用锁相调频器。本文对锁相调频器进行了理论分析,并对其中的关键技术问题提出了解决办法。     

The Measurement of the Electric Activity of the Olfactory Bulb in Free Swimming Carp (Cyprinus Carpio L.) by Underwater Telemetry Systems

A direct-wired telemetry system and a radio telemetry system were constructed in an attempt to measure the electric activity of the odfactory bulb in free swimming carp. The direct-wired telemetry system had a long, flexible, insulated signal wire, a high-gain ac amplifier, and a recording instrument. The radio telemetry system consisted of a transmitter which employed a single-channel pulse-frequency modulation (PFM)/FM and a receiver which contained a commercial phase-locked FM tuner, a frequency-voltage converter, a low-pass filter, and a recording instrument. The main specifications of the transmitter were as follows: main carrier frequency, 78 MHz; subcarrier pulse frequency, 2.5 kHz; input impedance, 2 ×107 ?or more; dynamic range of input, 0.01-3.00 mV; weight, 3.2 g in water; working life, about 50 h when supplied by two silver oxide cells of 1.5 V, 75 mA/h; working range, 3 m in city water. The overall frequency characteristic of the radio telemetry system was 0.24-74 Hz (?3 dB). By means of these telemetry systems, the first satisfactory records of electric activity were taken from the olfactory bulb in free swimming fish.     

Micropower integrated circuits for an implantable bidirectional blood flowmeter

The measurement of bidirectional bloodflow on a chronic basis is of critical importance in research on cardiovascular and pulmonary diseases. An implantable bidirectional Doppler ultrasonic bloodflow system was designed to satisfy this need. The system utilized quadrature detection to provide the directional information and multiplexing to transmit the quadrature signals over one FM telemetry link. A new family of three 1 V micropower bipolar integrated circuits were designed to implement the RF amplifiers, square law detectors, /spl plusmn//spl pi//4 phase shifters, audio amplifiers, a multiplexer, and the FM transmitter required for this system. An implanted system was used to measure pulsatile bidirectional bloodflow on a canine descending aorta. The results compared well with those in the literature and with a percutaneous EM flowmeter.     

S波段遥测发射机调制频偏及非线性测量

调频参数的测量,诸如调制频偏、非线性失真、频率响应,通常可采用KF调制度测量仪进行测量。当载频高于1300MHz或频偏大于400kHz时,目前还无法用仪器直接测试。本文介绍一种用频谱仪测量S波段遥测发射机的调制频偏及调制非线性的方法。     

The design and use of an FM-AM radiotelemetry system for multichannel recording of biological data

A multichannel telemetry system for EEG recording has been constructed for study of animal or human behavior correlates under natural, unrestrained conditions. To be useful in research of this kind, the transmitted radio signal must be independent of the environment, so that changes in antenna loading and in signal level cause no artifact. Standard IRIG proportional-bandwidth FM subcarrier channels are used. These subcarriers are generated by twin-T oscillators, modulated in turn by the amplified data signals. The FM subcarriers are then linearly summed and impressed upon a crystal-controlled AM transmitter. The system is also relatively insensitive to major shifts in supply voltage. Wherever possible, fabrication was by means of integrated circuits, thus reducing the bulk of the modules.     

经济实用的调频发射机远程监控系统

为了提高无人值守机房的安全播出水平,构建了一套经济实用的调频发射机远程监控系统。扬州广电传媒集团发射传输部本着低成本原则,利用现有设备,仅添加一台串口服务器即实现无人值守机房调频发射机远程监控。该设计不仅降低了成本,同时还提高了系统可靠性和安全性,为中小型广播电视台站实施远程监控提供了参考。     

Telemetry of human electrocardiograms in aerial and aquaticenvironments

A technique for human electroencephalogram (ECG) telemetry that is equally useful on land and in water (i.e. amphibious ECG telemetry) with a single transmitter was developed. For the ECG on land, an electromagnetic wave of 79 MHz FM VHF was used, while for the ECG under water, a 77-kHz FM current was used. The VHF was received by an aerial of an FM radio and the current by two underwater antennas along course-marker ropes. When a subject jumped from a diving platform into the water, continuous recording of ECG signals was possible with only a short time disturbance of the signals due to change in posture of the subject before jumping. This indicates rapid switching from electromagnetic to conductive transmission. The ECGs on land and during surface or underwater swimming showed a clear difference in the QRS complex and T wave     

An FM Telemetry Demodulator for Telephone Pacemaker Clinics

An economical wideband FM telemetry demodulator has been developed for use in telephone telemetry pacemaker clinics. The device features wide bandwidth to accommodate most commercial FM telephone telemetry transmitters, automatic gain control, callback and system test capabilities.     

OFDM for data communication over mobile radio FM channels. I.Analysis and experimental results

The performance of OFDM/FM modulation for digital communication over Rayleigh-fading mobile radio channels is described. The use of orthogonal frequency division multiplexing (OFDM) over mobile radio channels was proposed by Cimini (1985). OFDM transmits blocks of bits in parallel and reduces the bit error rate (BER) by averaging the effects of fading over the bits in the block. OFDM/FM is a modulation technique in which the OFDM baseband signal is used to modulate an FM transmitter. OFDM/FM can be implemented simply and inexpensively by retrofitting existing FM communication systems. Expressions are derived for the BER and word error rate (WER) within a block when each subchannel is QAM-modulated. Several numerical methods are developed to evaluate the overall BER and WER. An experimental OFDM/FM system was implemented and tested using unmodified VHF FM radio equipment and a fading channel simulator. The BER and WER results obtained from the hardware measurements agree closely with the numerical results     

调频激励器的设计与实现

数字调频激励器是调频发射机的信息处理核心,直接决定发射机性能的优劣。另一方面,它又部分承担发射机故障处理及报警的职责,即调频激励器应对自身及发射机整机进行监控。在发射机运行出现故障时需进行自身调整,从而保证发射机运行的正常和安全。阐述了采用直接数字式频率合成器（DDS）软件调频方式对模拟信号进行调制。DDS产生的信号频率精度很高,且与晶体振荡器的稳定度相同,可达10-6以上。其单片机控制可以随意切换载波频率,频偏,调制度等,并且可以容易地实现。该系统的测试结果令人满意。