Digital frequency synthesizer
(57) Abstract:Digital frequency synthesizer relates to electronic computing, designed for the synthesis of signals with frequency modulation and can be used in radar, adaptive broadband communication systems. Digital frequency synthesizer comprises a generator of clock pulses, the delay block, the block of continuous memory, preset counters, multiplier codes, the drive, the code Converter, digital to analog Converter, a low pass filter and a memory register. Technical result achieved - increase functionality and improve performance. 4 Il. The invention relates to electronic computing, designed for the synthesis of signals with frequency modulation (FM) and can be used in radar, adaptive broadband communication systems.Known digital frequency synthesizers containing two blocks of constant memory, two drives, two memory register, the counter with the lower frequency clock generator pulses, the delay block, the code Converter /1/.The closest technical solution (prototype) to the proposed AVL, the preset counters, the code Converter, a memory register, a d / a Converter, low pass filter, the clock and the delay block /2/.However, the known frequency synthesizers do not provide the ability to quickly control the frequency and rate of change of frequency.The invention allows to extend the functionality of the frequency synthesizer and to increase its speed.The positive effect of raising the rate of change of frequency compared with the existing frequency synthesizers is achieved by introducing additional operations of summation in the calculation of the phase signal and the two exceptions summary operations before multiplication of the input codes. For this purpose connected in series generator of clock pulses and the delay unit, connected in series block of continuous memory, preset counters and the multiplier codes, serially connected d / a Converter and low pass filter, a memory register, the drive, the code Converter, while the counting input of the counter preset is connected to the first output of the delay block, the third, che is noites codes, respectively, unit permanent memory and the output of the lowpass filter are respectively the input and output of the frequency synthesizer, and outputs the preset counters are connected to the inputs mnimogo multiplier codes, outputs whose works are connected to information inputs of the drive, the outputs of which are connected to the information input of the code Converter whose outputs are connected to respective inputs of the digital to analog Converter clock input drive is connected to the sixth output of the delay unit and the output signal of the older iconic discharge drive is connected to the control input of the inversion of the code Converter, the input of the memory register is the input of the digital frequency synthesizer, and the second output of the delay block is connected to a clock output of the memory register.These technical solutions either in the scientific or patent literature have been identified.In Fig. 1 shows a structural diagram of a digital frequency synthesizer. In Fig. 2 - graphs and cyclic changes of frequency in time. Fig. 2A - heterodyne receiver, Fig. 2B - in module of the transmitter, Fig. 2B - the receiver output.Digital frequency synthesizer includes: the chick with the advanced installation
5. The multiplier codes
7. The code Converter
8. D / a Converter
9. The lowpass filter
10. The memory register
Digital frequency synthesizer includes serially connected clock 1 and the delay unit 2, connected in series DC memory 3, preset counters, 4 inputs mnimogo multiplier codes 5, the outputs of the multiplier works codes 5 and inputs the drive 6, the code Converter 7, a d / a Converter 8, the low pass filter 9, and the high order bit of the accumulator 6 is connected to the control input of the inversion transformation codes 7. The outputs of the memory register 10 is connected to the inputs of multiplier multiplier codes, and the first output of the delay unit 2 is connected to the clock input of the counter 4, the second to the clock input of the memory register 10, the third, fourth and fifth to the clock inputs mnimogo, the multiplier and the product of multiplier codes 5, respectively, the sixth output of the delay unit 3 is connected to the clock input of the drive 6. Inputs digital frequency synthesizer are the address inputs of a block of continuous memory 3 and the inputs of the memory register 10, and the output of the lowpass filter 9 anserinae unit permanent memory 3 receives the address of the sample Xidefining the synthesized frequency-modulated signal, simultaneously code Yiof the control program is written to the memory register 10. Clock 1 generates a sinusoidal reference signal of frequency ftand the delay unit 2 performs signal conversion clock pulses of the form "meander" and the passing time of a sequence of clock pulses at 1. ..6 outputs, thus providing a noise reduction switch counter 4, multiplier codes 5 and the drive with indeterminate States on their outputs.At the output of the preset counters 4 code number X is updated in accordance with a clock frequency ft< / BR>X = Xi+ T
where Xi- constant recorded in the unit's permanent memory 3;
T - the number of the clock pulse (T= 0, 1, 2, 3...).Then at the outputs of the multiplier works code 5 code works with each subsequent clock pulse is changed as follows:
P = X*Y = (Xi+ T)*Yj.From the output of the multiplier code 5 code works arrives at the inputs of the drive 6, which in this frequency synthesizer is a phase calculator. The outputs of the memory 6 to the/SUB>*Yj*T + Yj*T2.The high order bit of the result of the summation of the drive 6 is supplied to the control input of the inversion of the code Converter 7. The rest of the N high-order bits (N is the number of bits of the DAC) through the code Converter 7 is supplied to corresponding inputs of a digital to analogue Converter 8, which generates an analog speed signal "sawtooth" shape, if you turn off the sign bit Ssgn and the signal "triangular" form, if you are connected to the sign bit Ssgn.The phase of the synthesized signal is changed according to the law
= S = X*iY*iT+Y*iT2.It should be noted that the result of summation is changed in the interval
S = 0...2N, which corresponds to the phase change = 0...2.If you accept 0= X*iYi- primary circular frequency,
0.5 = Yi- the rate of change of cyclic frequency,
t = T, then the phase will change by the formula
=0t+0,5 t2.The analog signal passes a low-pass filter 9, which transmits the output of the frequency synthesizer only the first harmonic of the generated signal. The developed device synthesizes the signal the maximum amplitude of the synthesized signal.A feature of the claimed frequency synthesizer is that it can be used to transmit information. You need two such frequency synthesizer, one of which is used as the modulator of the transmitter and the other as a heterodyne receiver.The change of frequency in the receiver is performed according to the formula
0(t) = Xi0Yi0+Yi0t.The change of frequency in the transmitter is performed according to the formula
1(t) = xi0Yi1+Yi1t.
where Yj1= Yi0+ c;
Yi1code frequency information signal;
c - code information symbol.Therefore, the receiver can distinguish the difference signal
.Thus, changing the code of the multiplier Yiin the synthesizer of the transmitter, you can send an informational message synthesized FM signal (Fig. 2A, 2B, 2C).Literature
1. RF patent 2058659, CL H 03 B 19/00, 1996.2. USSR author's certificate 1774464, CL H 03 B 19/00, 1992. Digital frequency synthesizer containing serially connected clock and the delay unit, connected in series DC memorizing counter with pre-UCHASTOK, the memory register, the drive, the code Converter, while the counting input of the counter preset is connected to the first output of the delay block, the third, fourth and fifth outputs of which are connected to the clock inputs of the write mnimogo, the multiplier and the product of multiplier codes, respectively, the inputs of the block of continuous memory and the output of the lowpass filter are respectively the input and output of the frequency synthesizer, wherein the outputs of the preset counters are connected to the inputs mnimogo multiplier codes, outputs whose works are connected to information inputs of the drive, the outputs of which are connected to the information input of the code Converter, the outputs of which are connected to respective inputs of the digital to analog Converter clock input drive is connected to the sixth output of the delay unit and the output signal of the older iconic discharge drive is connected to the control input of the inversion of the code Converter, the input of the memory register are input digital frequency synthesizer, and the second output of the delay block is connected to a clock input of the memory register whose outputs are connected to the inputs of multiplier multiplier codes.
FIELD: radio communications.
SUBSTANCE: device has phase-inverse cascade, two-tact cascade, active elements of which at output are connected in parallel and connected to load, while source electrodes of active elements are connected to outputs of phase-inverse cascade and through source resistor to common point of device, while control electrodes of active elements through blocking capacitors are connected to common point of device.
EFFECT: broader functional capabilities, higher efficiency.
FIELD: radio receiving devices for relative phase-keyed signals.
SUBSTANCE: proposed reference wave shaper for coherent detection of 180 deg. relative phase keyed signals has frequency doubling unit, second harmonic filter, phase shifter, power amplifier, parametron, electronic switch, low-pass filter, and phase detector.
EFFECT: eliminated phase jump, enhanced noise immunity in signal reception.
1 cl, 1 dwg
FIELD: radio engineering; computerized measuring systems.
SUBSTANCE: proposed method involves conversion of linear signal into nonlinear one by parametric addition of linear signal with pumping signal and using them to act upon nonlinear formation created on the way of linear signal propagation in the form of man-made ionized formation or magnetic base plasma formation, parameters of linear and pumping signals being variable; linear signal and/or pumping signal is controlled by nonlinearity parameters of nonlinear formation in compliance with given analytical equation describing type of nonlinearity of nonlinear signals being generated; linear signal is, essentially sine-wave or pulsed signal.
EFFECT: ability of generating nonlinear signals with desired type of nonlinearity.
4 cl, 1 dwg