adjust the other constants of the circuit so that the secondary circuit is approximately in resonance with the received oscillations. This may be done either by precalibration of the constants, or by means of a wave-meter and detector. No exact tuning is necessary, however, as the revolving condenser will, within limits, by reason of rotation, find the exact point of resonance.
In Fig. 2 I have shown a modification of my apparatus, which consists in placing the revolving condenser in another secondary circuit containing the indicating instrument. In that figure the aerial is shown a 1, the aerial tuning inductance at 2, the aerial series condenser at 3, the aerial being earthed at 4. The primary of the oscillation transformer is shown at 2a. At 14 I have shown a coupling coil connected in series in the aerial circuit, which coil is in inductive relation with the secondary 15, which secondary is shunted by the revolving condenser 8. The relation of this secondary circuit to the aerial circuit may be direct or conductive, as well as inductive. Any convenient detecting secondary circuit may be used, as for instance that illustrated, which includes a telephone or other indicating instrument 6 which may be shunted by condenser 7, a variable condenser 16, and a crystal or other detector 17. The latter is not essential, although I prefer to use a detector because of its effect upon the operation of the telephone. In the operation of the apparatus shown in Fig. 2, the aerial circuit is tuned to the wave length of the incoming oscillations, and the circuit containing the revolving condenser is adjusted so that for certain positions of the revolving condenser this circuit will be in resonance with the aerial circuit. In this way, when the condenser is revolved, at certain times the energy will be diverted from the detector circuit and caused to flow through the revolving condenser circuit, thus producing, by periodic variations of the constants of the revolving condenser circuit, a weakening and strengthening of the energy pulses in the detecting circuit and consequently audible signals of a frequency proportional to the speed of the condenser.
In Fig. 3 I have shown another modification of my apparatus which consists in placing the revolving condenser in the aerial circuit. Referring to Fig. 3, the aerial is shown at 1, the aerial tuning inductance at 2, the primary of the oscillation transformer at 2a. In series with the aerial is connected the revolving condenser 8, which is connected to the earth at 4. The secondary circuit may be of any suitable type and may contain the secondary of the oscillation transformer 5, a telephone or other indicating instrument 6 which may be shunted by a variable condenser 7, and any suitable detector 17, which, however, may be omitted. In this construction the aerial is periodically thrown into or out of resonance with the received oscillations, thus producing pulses in the detecting circuit of a frequency proportional to the speed of rotation of the revolving condenser.
In Fig. 5 I have shown an application of the revolving condenser to a circuit ordinarily used for the reception of damped oscillations. When arranged as shown in this figure the circuit may be used to receive damped oscillations if the revolving condenser be stopped at a point of suitable capacity; or it may be used to receive undamped oscillations if the revolving condenser be set in motion. This arrangement, therefore, is a convenient one for use at stations where both damped and undamped oscillation must be received at different times.
Referring to Fig. 5, 1 is the aerial, 2 the aerial tuning inductance and the primary of the oscillation transformer, 3 the aerial series capacity, and 4 the earth. The secondary of the oscillation transformer is shown at 5, this secondary being shunted by the revolving condenser 8. Connected in the secondary detecting circuit is a detector 17, a telephone or other indicating instrument 6, and a variable condenser 7 shunting the telephone.
While I have illustrated my invention in certain specific forms, I do not wish to be limited to these forms since it will be evident to those skilled in the art that changes in the specific connections may be made without departing from the spirit of my invention. One of these changes, for instance, as I have already indicated, would be the variation of the inductance of the circuit instead of the capacity. This may be conveniently done by the use of a revolving inductance of the variometer type, which may be connected in the detecting circuit, in the aerial circuit, or in another secondary circuit coupled to the aerial.
What I claim is:
1. Means for receiving electrical oscillation of a given frequency comprising a circuit containing the inductance and capacity, and means for periodically and progressively varying the capacity of said circuit to put said circuit into a condition of resonance with the received oscillations at intervals of a frequency other than the frequency of the received oscillations, and a detector associated with said circuit and responsive to the frequency of said intervals.
2. Means for receiving electrical oscillations of a relatively high frequency comprising a circuit containing inductance and capacity, and means for periodically and