SU441639A1 - Signal searching and tracking device - Google Patents

Description

one

This invention relates to radio receivers and can be used in high-precision devices for automatic frequency or phase adjustment.

According to the main author. St. No. 383197, a device for searching and auto-tracking a signal is known.

However, such a device does not have a high enough search speed due to the considerable recovery time of the initial state of the key relay.

The aim of the invention is to increase the speed of the loiske.

This is achieved by the fact that in the proposed device between the kipp-relay and the emitter follower a circuit "OR with a capacitor at the output is introduced, the second input of which is connected to the differentiating chain of the second channel through the kipp-relay connected to the second input of the main kip-relay through the differentiating amplifier .

FIG. 1 shows a functional diagram of the proposed device; in fig. 2 - time diagrams.

The device (the search and auto-propagation of the signal contains an emitter follower 1 connected through a narrow-band filter 2 with an amplifier 3 with phase outputs, to one of which (a channel consisting of a Schmitt trigger 4 is connected, differentiates 2

5 and Kipp relay 6, and to another output a channel consisting of a Schmitt trigger 7, a differentiating chain 8 and a Kipprele 9 connected to the second input of the first channel Kipprel through a differentiating amplifier 10, OR an output, an emitter follower on a transistor 13, a sawtooth generator, comprising a capacitor 14 with a charging circuit, consisting of a secondary winding of an impulse transformer 15, resistors 16, 17 and a diode 18, and a discharge circuit in the form of a stalled blocking generator on the transistor e 19, resistors 20, 21,

22 and transistors 23, 24, forming the output emitter follower.

FIG. 2, and the input signal is represented; on fit. 2, b and c - voltages at the paraphase outputs of the amplifier 3; in fig. 2, gl — respectively, the voltage at the outputs of blocks 4-11; in fig. 2 m is the output voltage of the device.

The search and auto-tracking device operates as follows.

In the absence of a signal in the search mode, the voltage at the output of the narrowband filter 2 does not reach the trigger threshold of Schmitt triggers 4 and 7. In this case, the sawtooth generator operates using a fast discharge circuit through a blocking generator on the transistor 19. The capacitor 14 at the same time charges is supplied from the power source through resistors 16, 17, diode 18 and the winding of a pulse transformer 15. When the voltage on the capacitor 14 is reached, the unpowered voltage of the transistor 19 causes a blocking process, and the capacitor 14 quickly discharges It is passed through a small input impedance of the blocking generator. The sawtooth nanrl arising on the capacitor (Fig. 2, g) through the emitter follower on transistors 23, 24 is transmitted to the output of the device.

When a useful signal is input to the device (Fig. 2, a), the voltage within the hold band begins to vary within wide limits. When the frequency (phase) of the slave generator changes in accordance with the voltage of the asymmetric type of voltage, the voltage at the input of the Schmitt trigger 7 begins to increase in i. At the moment when the threshold is reached, this process stops (Fig. 2.6, g, I), as by differentiating the leading edge of the trigger pulse 7 with the help of the differentiating depot 8, the kipp-relay 9 is started and the process of further charging of the capacitor 14 is terminated due to the diode 18 being locked with an impulse kipp-relay 9 that passed through the “ILR1 11” circuit and an emitter follower on the transistor 13. The pulse of the kip-relay 9 (z - z) is slightly longer than half the period of a constant slow discharge of the capacitor 14. After This pulse of the kip-relay 9, its falling edge generates pulses in the differentiating amplifier 10 (Fig. 2, k) and starts the Kip-relay 6 (Fig. 2, e), the pulse duration of which slightly exceeds half the period of the constant slow discharge of the capacitor 14 The impulse of the Kip-relay 6 through the OR or emitter repeater circuit on the transistor 13 closes the diode 18. From the moment 4 to the moment tt the capacitor 14 is slowly discharged through the parallel-connected resistor 22 and the input resistance of the output emitter.

At the moment of time, the Schmitt trigger 4 is triggered, and its leading edge, differentiated by differentiating chain 5, produces a cut-off of the Kip-relay 6 (Fig. 2, d, g, e}), after which the diode 18 opens.

the fast charge circuit of the capacitor 14 in the sawtooth generator, and the charging of the capacitor 14 begins until t t5, at which Schmitt trigger 7 is triggered, and the entire cycle of operation of the device repeats until the signal disappears.

If the frequency (phase) of the signal changes, the device monitors this change during the signal search interval (from to), and the triggering times of Schmitt triggers 7 and 5 in tracking the signal are shifted. When the signal disappears, the device automatically and without delay enters the signal search mode, since the supply of trigger pulses to the dimming relay 9 and cut-off pulses to the bluetooth relay 6 ceases. The total duration of the electrical signals from the relay relay 9 and 6 at the output of the OR 11 circuit the absence of a reset pulse at the output of the differentiating depot 5 is longer than the time interval equal to the period of slow discharge of the capacitor 14, so that the reset pulse is always located inside the kip-relay pulse 6. For providing zero medium its frequency mismatch values in the auto-tuning system, the trigger thresholds of Schmitt triggers 7 and 4 are chosen the same, and their values are selected from the condition that the device is protected from noise in the passband of filter 2. The capacitor 12 smooths the output voltage of the "OR 11" circuit between pulses Kinp-relays 9 and 6. The smallest porosity of the impulses of the Kip-relays 6 and 9 is equal to approximately two, even with a significant difference in the periods of the sawtooth voltage generator in the autosearch mode and auto signaling signal. In this way, a signal search is performed in a very short time.

Subject invention

The device for searching and tracking a signal by aut. St. No. 383197, characterized in that, in order to increase the search speed, an OR circuit with an output capacitor, the second input of which is connected to the differentiating chain of the second channel via the Kipp relay connected to the second input of the main circuit, is introduced between the Kipp relay and the emitter follower -relay through differentiating amplifier.