SU587416A1 - Compensation-type radiometer - Google Patents

Description

one

The invention relates to radio engineering and can be used in devices for measuring weak noise signals against the background of internal receiver noise.

Known compensation radiometer, 5

containing a series-connected band-pass filter, a high-frequency path, a detector, a compensation unit, to the second input of which a compensating voltage source is connected, and the output signal is connected to a u.j signal through a low frequency filter. However, this compensation radiometer has a low sensitivity.

The purpose of the invention is to increase the sensitivity of the compensation radiometer.

For this, in the compensation radiometer, the input of the source of the compensating voltage is connected to the output of the high-frequency path,

at the same time, the source of the compensating voltage - M is made in the form of series-connected bandpass filter and detector.

Fig. 1 shows a structural electronic circuit. The compensation scheme is a radio-metric. ra; cha figs. 2 - mutual arrangement 25

filter bandwidths and a high frequency path.

The proposed compensation radiometer includes a band-pass filter 1, a high-frequency path 2, a detector 3, a compensation block 4, a low-pass filter 5, a recorder 6 and a compensating voltage source 7 made in the form of serially connected band-pass filter 8 and a detector 9,

The band-pass filter 1, the high-frequency path 2, the detector 3 and the compensation unit 4 are connected in series. A compensating voltage source 7 is connected to the BTOpoNfy input of the compensation unit 4, and a low-pass filter 5 and a recorder 6 are connected to the input switch. The input of the compensating voltage source 7 is connected to the output of the high-frequency path 2,

The bandwidth of the band-pass filter 1l is less than the bandwidth of the path 2 of the high frequency Af The bandwidth of the band-pass filter 8L d, D1 and lies within the bandwidth of the 11H path 2 of the high frequency, and the band pass

The filter 8 is rebuilt from the bandpass filter 1 and the sum of the half-bands, filters 1 and 8 (Fig. 2). The proposed compensation radiometer works as follows.

FfoneaHufl. Noise signal is fed through 5 pes by the pass filter 1 to the input of the high frequency path 2, from the output of the high frequency path 2 a useful signal in the Afj band and

... v -, - lf

radiometer self-noise in the band Xd is fed to the band-pass filter 8. When ,, o

By this, the noise level varies according to the response to the amplification i of the high-frequency path 2. Bandpass filter 8 I performs noise selection of a compensated radiometer in the band Af, Ai -Af: 15 Thus, noise is selected throughout the transmission pass of path 2, high frequency with the exception of the band A | C, within which the spectrum of the useful signal is concentrated. G output bandpass filter 8 noise compensatory radiometer through the detector 8 is fed to the second input of block 4 compensation. At the same time, from the output of the high-frequency path 2, through the switch 3, the first input of the compensation unit 4 receives a useful signal against the background noise of the compensation radiometer.

In compensation block 4, the self-noise of the compensation of the ion radiometer is compensated by the voltage of the noise coming from the output of the detector 9 and the average value of the difference signal at the output of the low-pass filter 5 nporiopionally of the power of the useful signal.

The transmission coefficient of the band-pass filter 8 is chosen such that when there is no input signal at the output of the compensation radiometer, a zero signal is observed. J

Thus, the implementation in the proposed compensation radiometer of the selection of proper to noise and the use of their voltage as a compensating factor reduces to a minimum the effect of high frequency path gain factor fluctuations on the reception of a useful noise signal, thereby increasing the sensitivity of the compensation radiometer.

Claims (1)

Invention Formula A compensation radiometer containing a high-frequency path, a series-connected bandpass filter, a detector, a compensation unit, to the first input of which is connected to a source of low voltage, and a low-pass filter connected to a recorder that differs in that, with an increase in sensitivity, The input of the compensating voltage source is connected to the output of the high-frequency path, while the source of the compensating voltage is made in the form of a series-connected bandpass filter and detector. Sources of information taken into account in the examination :. 1 "Handbook of electronics. Ed. A.A. Kulikovskogo T. ZM., Erg and, 197O, p. 508, ig.2