Parts explanation
for Ultra High Accuracy Digital Clock (Ver2)
  PLL oscillator This is the PLL oscillator which is the heart of this clock. With this oscillator, the correct 10-MHz signal which sync6hronized with the color burst of the television signal is made. Generally, an error is said to be ±1 x 10-12 from ±1 x 10-11. In case of the precision of ±1 x 10-12, it takes 30,000 years for the error in 1 second to occur. For the details, refer to "PLL oscillator". TV tuner This is a small TV tuner. It is possible to receive VHF stations and UHF stations. The circuit this time uses only 1 station. As for the tuning, it is done by the voltage for the tuning. For all stations to be done in the tuning, about 28-V voltage is needed. However, this time, 12 V are used. As for the video signal, refer to "TV tuner". Case Acrylic board is used for the case. Battery Six nickel cadmium battery with 700mAH are used for the backup of AC power stop. Six batteries are connected in series. For the details, refer to "Backup battery". Rotary encoder This is a mechanical slide-type rotary encoder. It is used for the setting of a time. For the details, refer to "Circuit explanation of Digital dial". Time setting switch This is the switch of the non lock type which has an a-contact(make) and a b-contact(breakage). These switches are used for the setting in 0 seconds, the change of the time setting mode and so on. Speaker This is the small speaker to sound the music of the time signal. The input power of 1W is possible. Because it is small, the sound quality isn't good. Volume This is the variable resistor to adjust the volume of the time signal. Knob This is the knob which is used for the rotary encoder and the volume. Shielding wire This shielding wire is used to connect the audio signal of the television and the volume. A noise is mixed when not using a shielding wire for this part. Coupling capacitor for the picture This is the coupling capacitor to use when inputting the video signal which was received with the television tuner to the PLL oscillator. Generally, a video signal is connected with the PLL oscillator using the buffer amplifier. However, this time, it is connected only with the coupling capacitor. The purpose of this capacitor is the cut of the direct current. This capacitor is directly connected with the terminal of the tuner and the video signal input terminal of the PLL oscillator. The lead wire is covered by a Teflon tube to prevent contact with the other wire. RCA jack This is the jack to use to connect a television antenna. This jack is for the audio. However, this time, there is no problem because it doesn't watch a television picture. AC adapter This is the adapter to make the voltage of DC15V from AC100V. The adapter which was used this time is the type which used a switching regulator. However, because to pass a big electric current isn't necessary, it is to be OK with the type which used usual transformer and a rectifier. Power supply connector This is the connector to connect an AC adapter. This connector has more than one kind. The thickness of the central pin, the outside diameter and so on are different. It is necessary to confirm that the AC adapter can connect. Battery case This is the case to set batteries for the backup. Substrate This is the substrate to mount a television tuner, a PLL oscillator, a clock main unit, backup batteries. The TV tuner must do a ground connection with the PLL oscillator tightly because it handles a high frequency. It may use sheet copper. This time, I used a naked printed board. It is light compared with the sheet copper and the processing is easy too. There is no problem in the grounding. Stud This is the stud for the installation of the substrate to the case. These are used at the 4-corner and center. Operation mistake protector This is the protector to prevent from the operation mistake of the setting switch in 0 seconds, the time setting switch. It is made with bent acrylic board. Suspension metal fittings This is the metal fittings to fix the chain to suspend a clock. Chain for the suspension This is the chain to suspend a clock .It is to be OK rather than the chain, too. Label This is the label for the control panel. |