• Comprehensive Built-In-Test(BIT)
  复杂的内部测试(BIT)
• Selectable Gain. 
  选择性增益
• Automatic Protection Mode During RF Overload.
  在射频超载的情况下，启动自动保护模式
  
• Automatic switching between Preselector and Postselectoe Modes for use with Transceivers.
  为收发信机使用提供预选与后选模式自动切换
  
• 1.75"x19" Rack Mount Package.
  1.75"x19"的可上机架机箱

　　The PPS-100 Pre/Postselector permits operation of co-located receivers and transmitters on frequencies separated by as little as 10%. When used with receivers, the unit functions as a preselector, providing an additional front end selectivity stage. This reduces the receiver desensitization and overload that would normally occur in the presence of strong adjacent RF transmissions. The unit is used as a postselector with transmitters. It rejects spurious outputs and broadband noise in the transmit signal before it reaches the power amplifier, thereby limiting interference to neighboring receivers. The PPS-100 performs both functions with a transceiver; it follows the radio's keyline and swithes between the preselector and postselector modes.
PPS-100预/后选器允许并将接收机和发射机的频率以小到10%来划分。当配合接收机使用时，该装置的功能作为一台预选器，提供一个额外前端选择阶段。这样就可以避免在出现邻近的射频的强烈发射时，通常会造成接收机的敏感度降低和超负荷运作。当配合发射机使用时，该装置则作为一台后选器。它将发射信号送达电源放大器以前，抑制其中的假输出信号和宽带噪音，以减少与邻近的接收机之间的干扰。PPS-100可同时为一台收发机提供以上两项功能，它伴随着无线电的KEYLINE，在预选和后选模式间切换。

　　The PPS-100 operates from 1.6 to 29.99 MHz. The unit offers a selectivity of 40 dB typical at 10% from the nominal tuned frequency, with an ultimate rejection of 70 dB typical. The input and output both have a norminal in-band impeddance of 50 ohms.
PPS-100在1.60至29.99MHz之间运行。该装置在铭牌规定的调谐频率范围内以10％的增长提供典型的40dB抑制，并可抑制高达典型的70dB。输入和输出均具有50ohms的阻抗。

　　The unit accepts frequency input 10 kHz increments, automatically tracking the radio's operating frequency via either serial (RS-232/422) or parallel BCD frequency information from its companion radio. Tuning time is 10 milliseconds maximum, making the PPS-100 suitable for Automatic Link Establishment (ALE) or Adaptive Applications. No octave or sub-octave filters are used.
该装置允许频率输入10k Hz的增量，从其通过其无线电的串口(RS-232/422)或其配对电台的并行BCD频率信息自动跟踪无线电操作频率。最大调谐时间为10毫秒，令PPS-100能够适应自动链路建立(ALE)或适应性应用。没有使用八音阶或副八音阶滤波器。

　　The Pre/Postselector offers two levels of gain; the level may be selected remotely or via the unit's front panel. The unit enters a Protection Mode whenever there a Protection Mode whenever there is an extreme RF overload. In this mode, the antenna port is open circuited, while the unit's internal input is grounded. A Bypass Mode can also be selected either via the front panel or remotely; the unit automatically switches to this mode while the internal self-test is in progress and when it is controlling radio switches to a frequency outside of the 1.6 to 30 MHz coverage range. Front panel LEDs signal the unit's present operating mode.
该预选器/后选器提供了两种电平的增益，电平的选择可通过遥控或前面板进行。一旦遭遇射频超载，该装置将进入保护模式。在该模式下，天线端口为开放电路，而该装置的内部输入则为接地。旁路模式也可通过前面板或遥控加以选择，该装备在自检过程和控制外部1.6至30MHz覆盖频率的无线电切换时，将自动切换到该模式下。前面板上的LED显示了该装置的目前操作状态。

　　The PPS-100 is housed in a 1.75"x19" rack mount package. Standard opaeration is from 115/230 VAC or from 12/24 VDC.
PPS-100包装于一个1.75"x19"可上机架的机箱内。在115/230VAC和12/24VDC下进行标准操作。