JPS59183533A - Tracking oscillator - Google Patents

Abstract

PURPOSE:To track an output to a high frequency input signal with high accuracy at all times by using the high frequency input signal as a reference signal to output a discriminating signal, and using its output as a correcting signal to feed back the output to a broad band oscillator. CONSTITUTION:An output of a broad band frequency discriminating circuit 40 via a low pass filter 38 being an output of a mixer 37 is a discriminating output signal proportional to the difference between the inputted high frequency signal and an output signal of a broad band oscillator 8. A frequency correcting control circuit 6 uses a high frequency signal input timing outputted from a timing detecting circuit 13 and outputs the said discriminating output signal as a frequency correcting signal. The frequency correcting signal is added to a coarse tuning signal to tune the broad band oscillator 8 in advance and outputted from a frequency tuning control circuit 9 by an adder circuit 7 and controls the broad band oscillator 8 to be matched to a frequency of the input signal. The output of the broad band oscillator 8 is distributed by a power 3-distribution circuit 39 and fed back to a hybrid 34 and a tracking filter 31 of the broad band frequency discriminating circuit 40.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking oscillator that follows the carrier frequency of a high-frequency input signal while accurately matching it.

A conventional circuit of this type is shown in FIG. In the figure, il+ is a high frequency signal input terminal such as a continuous wave or pulse modulated wave, 0 is a power 2 distribution circuit, and (11) is a power? Distribution circuit (2), broadband tunable band/cus filters (3a) and (3b), r-envelope line detector (4a) and (
4b), in the video addition circuit (6): a frequency correction control circuit that amplifies or temporarily stores the output signal level of each frequency discrimination circuit; (7) is a frequency correction control circuit that amplifies or temporarily stores the output signal level of the frequency discrimination circuit; (9) is an addition circuit with a coarse tuning signal tuned to the center (fC) of the frequency discrimination range (lfb-AI), (8) is a wideband oscillator, (10
) is a high frequency signal output terminal.

Next, the operation will be explained.

The cylindrical frequency signal applied to the high frequency input terminal 7 is passed through a broadband tuned frequency discrimination circuit (II) having high frequency discrimination characteristics shown in FIG.
) The frequency is discriminated by K.

Frequency discrimination circuit 01) A set of bandpass filters (3al.

so that each filter output can be tuned to
m-type (positive/negative polarity) saturation line detector (4a),
(4b) is connected, and the output is video-added for instruction, so it is possible to obtain a discrimination output whose amplitude becomes positive or negative in proportion to the carrier frequency of the island frequency signal input.

Therefore, this discrimination output signal is used to generate a wideband tuned oscillator (8
) can be corrected and controlled to obtain an oscillation frequency that closely follows the input signal.

Since the conventional tracking oscillator is configured as described above,
In order to accurately match and follow the input signal frequency, it is first necessary to match the center frequency fc of the frequency discrimination path with the oscillation frequency caused by the coarse tuning signal l over a wide band. Furthermore, since the frequency discrimination characteristic is obtained by detuning two tunable filter characteristics and utilizing amplitude changes, the frequency discrimination sensitivity is influenced by the filter characteristics over a wide band, so the discrimination characteristic is not constant but fluctuates.

For this reason, the discrimination sensitivity at the center frequencies fa and fa of the discrimination characteristics fluctuates, resulting in drawbacks such as the inability to perform accurate frequency correction control for the high frequency input 1d8.

This invention was made in order to eliminate the drawbacks of the conventional ones as mentioned above. Discrimination characteristic 1c, which is the center of the discrimination characteristic What to do?The output of the broadband tuned oscillator is all fed back to the frequency discrimination circuit, and a discrimination signal proportional to the frequency difference between both signals is obtained, which is fed back to the oscillator as a frequency correction signal, thereby constantly The purpose of this invention is to provide a frequency tracking oscillation signal that can accurately track a high frequency input signal.

An embodiment of the present invention will be described below with reference to the drawings. O8
In the figure, (1) is a high frequency signal input terminal such as continuous wave or pulse modulated wave, (2) is a power 2 distribution circuit, 01 is a power 2 distribution circuit), mixers (88a) and (88b),
0°Aθ°hybrid diagram, low pass filter)%”
flB/, Yu,. )
, a wideband frequency discrimination circuit consisting of a mixer @ and a discharge band pass filter, and (6) a timing detection circuit for the high frequency input (1 barrel is controlled by the frequency discrimination circuit to output the discrimination output signal of the frequency discrimination circuit). a frequency correction circuit for amplification or temporary storage; (7) is an addition circuit for adding the output signal of the frequency correction circuit and a coarse tuning signal tuned to the center CfQ of the frequency discrimination range output from the frequency tuning control circuit (9); (8
) is a wideband oscillator, ■ is a power 8 distribution circuit, and 6Xl is a tracking filter that hides in the reference high frequency signal% (10
1 is a high frequency signal output terminal.

Next, the operation will be explained.

The output signal of the frequency tuning control circuit (9) is obtained and the adder circuit (
711d controls the broadband oscillator (8) so as to tune the frequency to fc in advance. Also, the tracking filter 0υ is the output signal of the frequency tuning control circuit (9) and the power 3
center 'kf' by the output of the wideband oscillator (8) which is distributed by the divider). VC synchronized.

, the frequency (f) at which the high-frequency signal applied to the high-frequency input terminal il+ exists within the band of the tracking filter.
, ), it passes through the tracking filter 0υ and is discriminated by the wideband frequency discrimination circuit ).

The high frequency signal input to the wideband frequency discrimination circuit iw (ring 1a
+1t (however, ω, = 2πf, )) is distributed to the power 2 distribution circuit) and is then distributed to the mixers (38aj and (g s
b) and is mixed with the output of the Oo/9oO hybrid (b). Here mixer (83a) and (881
: +3 is input to 07i9oO The output of the hybrid (up to) is the output of the wideband oscillator (8) (Sinωqt (however, ωc = 2RIc)) kOo or 90' phase change jl', Sinωat (00 phase change ) is input to the mixer (8gb), and aosωat (phase change of 900) is input to the mixer (Baa), the outputs of the mixers (88a) and (llb) are given by the following equations.

Crab output from mixer (881) Sinωct x Si
nω1t=4−(aos(ωC+ωL)t+aos(ω
C-ωL)1)-------111 Mixer (8B a) output crab aOSωctx81n
ω1t-4(sin(ωO+(11,)t+5in(ω
C-ωrit) --------(2+Mixer (Baa)
The output of is a low-pass filter (to) and a mixer (881).
) has a high-pass filter (to) with a characteristic of 6-to-1 ctave, so what is input to the mixer (b) is 51n (ωC - ω1) of the output components of the mixer (88a).
)t, and among the output components of the mixer (gsb), (
ωC-ω1)stn(ωC-ωρt.

Therefore, the output of the mixer (b) is given by the following equation.

Crab coming out of mixer (b) (ωC-to 1) s 1n
COO-ωL)t-E! in(ωC-ω,)t-+-C
ωc-ω1) (l-cos(ωC-ωt)t)---
low-pass filter (to) at the output of ta+mixer)
Therefore, the output of the wideband frequency discriminator (8) is based on the difference (ωC
Only the discrimination output signal (DC component) proportional to -ωρ can be obtained.

Next, the same wave number correction control circuit (6) amplifies the discrimination output signal at a predetermined amplification degree using the timing of the high frequency signal input output from the timing detection circuit (No. 1). The signal level (for example, the time between pulses in pulse input) is maintained and output as a frequency correction signal.

The same wave number correction signal is added to the coarse tuning signal outputted from the frequency tuning control circuit (9) in advance to tune the wide band oscillator (8) to fc in the same wave number control signal addition circuit (7). 8) Control to match the frequency of all input No. 1.

The output of the wideband @ cutter (8) that matches the high frequency output terminal is divided by the power 8 distribution circuit ■, and the output is sent to the wideband frequency discrimination circuit (go7), hybrid (to), and tracking filter Cυ. will be returned.

Therefore, the high frequency output terminal can always obtain an inter-office wave output that accurately follows the tilted wave frequency of the inputted oscillation signal.

As described above, according to the present invention, in the frequency discrimination circuit, the high frequency human power 1d reference signal is outputted to the discrimination 14'8', and the output is fed back to the wide 4JA oscillator as a correction signal. With this configuration, the effect of being able to always follow the high frequency input No. 1- with high accuracy can be seen.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional wideband tracking oscillator, FIG. 2 is an explanatory diagram showing frequency discrimination characteristics, and FIG. 8 is a block diagram of a wideband tracking oscillator according to an embodiment of the present invention. (1)--One high frequency R input terminal, +21--One power 2 distribution circuit, (8a) and (ab)--One tuning type bandpass filter, (Feng) and (4'b)--One Saturation line detector, +51--video adder, +61-m-frequency correction control (b) line. (7) -11 frequency system (+11 signal 2711 arithmetic circuit,
F8) ---1 broadband oscillator, +91--1 station wave number tuning control circuit, (10) --- inter-station wave signal output terminal, (11
)--1 wideband tuning frequency discrimination circuit, 11g1--1 power 2 distribution circuit, -111 timing detection circuit, 6 routes-tracking filter, (2)-m-power 2 distribution circuit, ($8a) and (88b)-mixer, (b)-1-0
°AO” Ibrid, (7)-m-low pass filter,
Zeng - Organized pass filter, working - Mixer, (to) -
m-low-pass filter, (2)-11' three-power distribution circuit, ■---wideband frequency discrimination circuit. Note that the same reference numerals in the figures indicate the same parts or parts corresponding to one part. Agent Masuo Ohatsu

Claims (1)

[Claims] A tracking oscillator that tracks the carrier frequency of a high-frequency signal input has a tracking filter at the signal input end that tracks the oscillator's output frequency as a center, and further has a frequency discrimination output based on the high-frequency input signal that has passed through the tracking filter. A tracking oscillator characterized in that the output of the oscillator is fed back to a discrimination circuit, and the output frequency of the oscillator is controlled by the discrimination output of the frequency discrimination circuit.