SU566200A1 - Frequency metering apparatus - Google Patents

Description

(54) DEVICE FOR MEASURING FREQUENCY

one

The invention is fire-based and can be used to measure the frequency of a signal against the background of fluo-noise noise.

A device for measuring is known.

frequencies containing N parallel channels, each of which consists of a series-connected filter and an amplitude detector, to the outputs of which a channel number identifying unit is connected, a frequency estimator shaping unit to which inputs of a frequency correction calculator and a channel number determining unit 1 are connected.

However, this device has a low frequency accuracy.

The purpose of the invention is to improve the accuracy of frequency measurement.

For this purpose, a frequency measuring device containing N parallel channels, each of which consists of a series-connected filter and an amplitude detector, to the outputs of which a channel number determining unit, a frequency estimation generating unit,

The inputs of which are connected to the frequency correction calculation unit and the channel number identification unit, additionally introduced N filters, a controlled switch, two phase meters and an adder, the inputs of the entered filters are connected to the channel filter inputs, the outputs of all filters through the controlled switch are connected to the phase meter inputs, exits.

which, through an adder, are connected to: a frequency correction calculation unit, and a switch control input is connected to a channel number determining unit.

FIG. 1 shows the structural electrical circuit of the device. for frequency measurement} in FIG. 2a shows the frequency, and in FIG. 25, the characteristics of two pairs of filters explaining the operation of the device.

The proposed device for measuring the frequency contains N parallel channels each of which consists of successively connected filters 1-1. - 1-N and amplitude detector 2-1 - 2- N j to the outputs of which the block 3 is connected & dividing the channel numbers, frequency estimation unit 4, the inputs of which have frequency correction calculation unit 5 and frequency identification unit 3, N additional filters 6-N 1 controlled switch 7, two phase meters 8, 9 and adder 10, and inputs 6-1- 6-N 5.:connected filters with the inputs of 1-1-1-N 1 filters; the channels, the outputs of all filters through the ynpatM switch 7 are connected to the inputs of phase meters 8, 9, the outputs of which are via; The adder 10 is connected to block 5, the frequency correction corrections, and the control input of the switch 7 is connected a unit 3 for determining the channel number.

A device for measuring the frequency works as follows.

The input of the device receives a mixture of signal with noise. The initial phase of the signal is equal to rd, and the frequency f is unknown, but n: 1: is measured within the resonant frequencies of the first and last pair of filters 1-1, tS-1 and 1-N, 6-N (fj). The signal amplitude is maximum at the output of those filter pairs 1-1 - 1- N, 6-1 6-: N, the resonant frequency of which is closest to the signal frequency. The signals from the filter outputs 1-1 - 1-N after detection come to the block 3 for determining the channel numbers, from where the channel numbers from the maximum and following the maximum signal amplitude are transmitted to the control switch 7. Switch 7 selects from all the channels connected to its input two pairs of channels in which the signal amplitude turned out to be the greatest, and connects them to the inputs of two phase meters 8, 9. Moreover, filter outputs with equal resonant frequencies are connected to each phase meter. Obviously, the frequency of the signal i is in the interval between the resonant frequencies of the selected filters, i.e. f i f: 1 Phase of the signal at the outputs of four you & the early filters are equal (see fig. 2 b) f.); , (, f2 (iO, Jni.Oi% (iM-fc), where S 2 is the steepness of the phase characteristics of the filters 1-1-1 -N. Sj is the steepness of the phase characteristics of the filters 6-1-6-N (see FIG. .2

Phase differences at the outputs of phase meters 8 9 will be respectively

i. «H) (u,) - r (i -.) (fcf,). , (At the output of the 1O adder we will have

A4Aif, fAVp, (S, -,) f2f, - (fHfO

or

(f, -f,),

Where

f

ug Sj-Sj, lo 2

Thus, at the output of the adder 10, a value is formed proportional to the frequency correction f.-f which is added in the frequency estimation unit 4 to the half sum of the resonant frequencies of the & early filters {and gives the true frequency fc fc-fo fo Formula of the invention The device for measuring the frequency, containing N parallel channels, each of which consists of a series-connected filter and an amplitude detector, the outputs of which are connected to the channel number limit, the frequency shaping unit, to the inputs of which A frequency correction calculation unit and a channel number determination unit are connected, characterized in that, in order to improve the measurement accuracy, N filters are additionally introduced, controlled by a switch, two phase meters and an adder, and the inputs of the entered filters are connected to the filter inputs of the channels The outputs of all the filters through a controlled switch are connected to the inputs of phase meters, the outputs of which are connected via an adder: to the frequency correction calculation block, and the UniVraySHayN input of the switch. connected to the channel number identification unit.1. Sources of information taken into account during the examination: 1. Spock “B. K. Questions processing radar signals. M., 197O, p. 1O2, fig. 4.3.