在Angular 7中，你可以使用RxJS库来实现Emitter和Poller的功能。下面是一个示例代码：

import { Component, OnInit, OnDestroy } from '@angular/core';
import { Observable, Subscription, interval } from 'rxjs';
import { takeWhile } from 'rxjs/operators';

@Component({
  selector: 'app-emitter-poller',
  template: `
    
Angular 7 - Emitter and Poller
    Start Emitter
    Stop Emitter
    Start Poller
    Stop Poller
  `,
})
export class EmitterPollerComponent implements OnInit, OnDestroy {
  private emitterSubscription: Subscription;
  private pollerSubscription: Subscription;
  private emitterInterval = 1000;
  private pollerInterval = 2000;
  private isEmitterRunning = false;
  private isPollerRunning = false;

  ngOnInit() {}

  ngOnDestroy() {
    this.stopEmitter();
    this.stopPoller();
  }

  startEmitter() {
    if (!this.isEmitterRunning) {
      this.isEmitterRunning = true;
      this.emitterSubscription = interval(this.emitterInterval).subscribe(() => {
        this.emitData();
      });
    }
  }

  stopEmitter() {
    if (this.isEmitterRunning) {
      this.isEmitterRunning = false;
      this.emitterSubscription.unsubscribe();
    }
  }

  startPoller() {
    if (!this.isPollerRunning) {
      this.isPollerRunning = true;
      this.pollerSubscription = interval(this.pollerInterval)
        .pipe(takeWhile(() => this.isPollerRunning))
        .subscribe(() => {
          this.pollData();
        });
    }
  }

  stopPoller() {
    if (this.isPollerRunning) {
      this.isPollerRunning = false;
      this.pollerSubscription.unsubscribe();
    }
  }

  emitData() {
    // 发送数据的逻辑
    console.log('Data emitted');
  }

  pollData() {
    // 轮询数据的逻辑
    console.log('Data polled');
  }
}

在上面的示例中，我们使用了RxJS的interval函数来定时发送数据和轮询数据。startEmitter和startPoller方法分别启动了Emitter和Poller的功能，stopEmitter和stopPoller方法停止了它们。emitData和pollData方法是具体的数据发送和轮询逻辑，你可以根据自己的需求进行定制。

请注意，在组件销毁时，我们调用了ngOnDestroy方法来停止Emitter和Poller，这是为了避免内存泄漏。